OPINION OF THE COURT
Until late 2008, Sprint Nextel Corporation (collectively with its operating subsidiaries, including Sprint Spectrum L.P., “Sprint”) included a flat-rate early termination fee (“ETF”) provision in its cellular telephone contracts, which allowed it to charge a set fee to customers who terminated their contracts before the end date stated in the contract. Because many consumers believed that flat-rate ETFs were illegal penalties, various class action lawsuits were brought against cellular phone service providers who charged flat-rate ETFs, including Sprint. In the case before us now (the “Larson” action), the plaintiffs entered into negotiations with Sprint, and, after five months of mediation, the parties decided to settle the matter for $17.5 million, pursuant to the terms of their agreement (the “Settlement Agreement”). Over objections lodged by several class members, the United States District Court for the District of New Jersey certified the settlement class and approved the Settlement Agreement. Objectors Lina Galleguillos, Antranick Harrentsian, and Michael Moore (collectively, the “Galleguillos Objectors”), along with Jessica Hall, appealed.1 Because the District Court did not adequately protect the rights of absent class members, we will vacate its order and remand the matter for further proceedings.
I. Background
A. Class Action and Settlement Agreement
A flat-rate ETF is one that does not vary during the term of the contract.2 At *113the time the Larson class action was filed, if a Sprint customer terminated a contract prior to the end of the contract term, Sprint would impose a flat-rate ETF of approximately $200. The Larson plaintiffs filed their suit in the District Court on November 5, 2007, alleging that the flat-rate ETFs charged by AT & T Mobility, LLC (“AT & T”) and Sprint were illegal penalties that violated the Federal Communications Act and state consumer protection laws. The Complaint was amended twice,' with the Second Amended Complaint, as discussed in greater detail herein, being filed by five plaintiffs (the “Class Representatives”). Each of the Class Representatives was charged a flat-rate ETF by Sprint.3
Sprint moved to dismiss the Larson aó^x tion pursuant to Rules 12(b)(2) and 12(b)(6) of the Federal Rules of Civil Pro-: cedure, but before the District Court rendered a decision on that motion, the Class Representatives and Sprint entered into mediation of the dispute, under the guidance of a retired judge of the District Court. After approximately five months of negotiations, on December 3, 2008, the parties agreed to settle the matter for $17.5 million, comprised of $14 million in cash and $3.5 million in activation fee waivers, bonus minutes, and credit forgiveness (collectively, the “Common Fund”).4 In addition to the monetary relief, the Settlement Agreement also enjoined Sprint from entering into new fixed-term subscriber agreements containing flat-rate ETFs for a period of two years, effective January 1, 2009.5 Along with ending the Larson action, the Settlement Agreement expressly resolved ten other lawsuits pending in various state courts, but it excepted certain claims that were being asserted in a California-only state court class action against *114Sprint captioned Ayyad v. Sprint Spectrum, LLP (“Ayyad ”).
The Settlement Agreement provided for four different categories of claimants, three of which are relevant to this appeal:6
Category I. — Claimants Who Paid an ETF
(Other Than Category III or IY Class Members):
A. Those Claimants who had a two-year term contract and terminated within the first six months of that contract term [or (B.) had a one-year term contract and terminated within the first three months of that contract term], and show sufficient proof that they paid an ETF including signing under penalty of perjury, [7] shall be entitled to a payment of $25 from the Common Fund; or to the extent such Settlement Class Members desire to activate a new service line with Sprint Nextel: (i) a waiver of the approximately $36 activation fee normally charged by Sprint Nextel in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber; and (ii) 100 free bonus minutes per month for the first year of that two-year contract....
C. Those Claimants who had a two-year term contract and terminated at any time between the seventh to the twenty fourth month of that contract term [or (D.) had a one-year term contract and terminated within the fourth to twelfth month of that contract term], and show sufficient proof that they paid an ETF including signing under penalty of perjury, shall be entitled to a payment of $90 from the Common Fund; or to the extent such Settlement Class Members desire to activate a new service line with Sprint Nextel: (i) a waiver of the approximately $36 activation fee normally charged by Sprint Nextel in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber; and (ii) 100 free bonus minutes per month for the first year of that two-year contract....
E. Those Claimants who cannot show sufficient proof that they paid an ETF, but sign under penalty of perjury that they paid an ETF will receive $25 cash payment; or to the extent such Settlement Class Members desire to activate a new service line with Sprint Nextel: (i) a waiver of the approximately $36 activation fee normally charged by Sprint Nextel in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber; and (ii) 100 free bonus minutes per month for the first year of that two-year contract. ...
Category II. — Claimants Who Were Charged an ETF But Did Not Pay the ETF:
A. Those Claimants who had a two-year term contract and terminated within the first six months of that contract *115term [or (B.) had a one-year term contract and terminated within the first three months of that contract term], and show sufficient proof that were charged an ETF, including signing under penalty of perjury, shall be entitled to $25 in credit relief, if the debt owed to Sprint Nextel is still owned by Sprint Nextel; or to the extent such Settlement Class Members desire to activate a new service line with Sprint Nextel:
(i) a waiver of the approximately $36 activation fee normally charged by Sprint Nextel in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber; and (ii) 100 free bonus minutes per month for the first year of that two-year contract....
C. Those Claimants who had a term contract and terminated after the seventh month of a two year term or terminated after the fourth month of a one year term, and show sufficient proof that they were charged an ETF, including signing under penalty of perjury, shall be entitled to (i) a $90 credit, if the debt owed to Sprint Nextel is still owned by Sprint Nextel; or (ii) to the extent such Settlement Class Members desire to activate a new line of service with Sprint Nextel: (i) a waiver of the approximately $36 activation fee normally charged by Sprint Nextel [for] free activation in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber; and (ii) 100 free bonus minutes per month for the first year of that two-year contract....
Category IV. — Claimants Whose Claim Arises After Notice to The Class But Before January 1, 2011:
H. Any Claimant who has a wireless line of service under a term contract entered into before January 1, 2009 and is subject to a flat-rate ETF that terminates after the close of the notice period, whose Approved Claim arose after the notice for approval of Settlement is provided to the Settlement Class but before January 1, 2011, and who swears under penalty of perjury that they were harmed as a result of the flat-rate ETF will be entitled to either: (i) a Sprint Nextel prepaid 90 minute Long Distance Calling Card to be purchased out of the Common Fund; (ii) to the extent such Settlement Class Member desires to activate a new line of service with Sprint Nextel, a waiver of the approximately $36 activation fee normally charged by Sprint Nextel in connection with obtaining a new two-year contract to become a Sprint Nextel subscriber and 100 free bonus minutes per month for the first year of that two year contract; or (iii) 300 free text messages per month for six months....
(Appellants’ Joint Appendix (“AJA”) at 283-291.)
The Settlement Agreement released Sprint from all ETF-related claims, including claims “arising from or relating to any decision by Sprint ... to impose [or] collect ... an Early Termination Fee, regardless of the basis for the customer’s claim that the fee should or should not be imposed [or] collected.” (AJA at 270.) The Settlement Agreement defined the “Claim Period” — that is, the time frame in which eligible claimants are entitled to file a claim to acquire the relief set forth in the Settlement Agreement — as “the period beginning 30 days after entry of the Preliminary Approval Order and ending 60 days after entry of the Final Approval Order and Judgment” related to the class settlement. (AJA at 263-64.) However, “the Claim Period d[id] not apply to Category IV benefits [, as] the deadline for submit*116ting a Category IV benefit Claim Form [was] January 1, 2011.” (AJA at 264.)
B. Class Certification and Settlement Approval
On December 8, 2008, the District Court entered an order preliminarily approving the Settlement Agreement and conditionally certifying the class under Federal Rule of Civil Procedure 23(b)(3).8 The settlement class was defined as follows:
All persons in the United States who are or were parties to a personal fixed-term subscriber agreement for a Sprint Nextel Wireless Service Account for personal or mixed business/personal use, whether on the Sprint CDMA network or Nextel iDen network, or both, excluding accounts for which the responsible party for the Wireless Service Account is a business, corporation or a governmental entity, entered into between July 1, 1999 and December 31, 2008 and whose claims relate in any way to an Early Termination Fee or use of an Early Termination Fee in a fixed-term subscriber agreement, and/or use or propriety of a fixed-term subscriber agreement whether the term was for the initial fixed-term subscriber agreement or subsequent extensions or renewals to the fixed-term subscriber agreement for whatever reason and/or who were charged by or paid an Early Termination Fee to Sprint Nextel, excluding only the Ayyad Class Claims and Persons whose right to sue Sprint Nextel as a Settlement Class Member is otherwise barred by a prior settlement agreement and/or prior final adjudication on the merits. The Settlement Class includes Persons who were subject to an ETF, whether or not they paid any portion of the ETF either to Sprint Nextel or to any outside collection agency or at all, and includes persons who are prosecuting excluded claims to the extent such persons have claims other than those expressly excluded.
(AJA at 7-8 (internal footnote omitted).)
After preliminarily approving the Settlement Agreement, the District Court set forth a schedule for the final approval process, including allowing class members to lodge objections to the class certification and the Settlement Agreement.
1. Initial Fairness Hearing
The District Court held an initial approval hearing (the “Initial Fairness Hearing”) over a four-day period in March of 2009. In papers filed prior to that hearing, the Galleguillos Objectors attacked many aspects of the adequacy of notice given to potential class members about the class action. In particular, they complained about the efforts undertaken by Sprint to produce a class member list for use in providing individual notice to class members.9 Following that hearing, on *117April 30, 2009, the Court issued an opinion agreeing with the Galleguillos Objectors that the initial notice plan (“INP”) did not comply with Rule 23(c)(2), which requires “the best notice that is practicable.10 Fed.R.Civ.P. 23(c)(2)(B). Accordingly, the Court issued an order denying final approval of the settlement without prejudice, and ordered counsel for the Class Representatives (“Class Counsel”) and Sprint to submit a new notice plan within 21 days.
In its opinion holding the INP deficient, the District Court instructed Sprint “to attempt to identify subclasses of individuals [who paid an ETF] and include individual notice to those persons.” (AJA at 4264.) The Court determined that, based on data provided by Sprint, it would be unreasonable for Sprint to compile a full list of class members from 1999-2008 because it would require six to twelve months of work at a cost of at least one million dollars. However, also based on records provided by Sprint, the Court found that “Sprint could conduct an inquiry as to whether ... it can identify specific subsets of customers — whether by year, geographic region, ETF paid, or type of contract — that are members of the class,” and the Court concluded that, “therefore ... the Galleguillos Objectors assertion] that partial class lists are as noticeable as complete ones ... has merit.” (AJA at 4260.)
The District Court meticulously reviewed case law discussing what constitutes a reasonable effort at sending individual notice to class members, and it held that “Rule 23(c)(2) [could not] be so easily circumvented by undertaking only an analysis of identifying each and every class member, rather than some or most class members.” (AJA at 4263.) Instead, the Court said that:
Sprint must do more than it has done thus far ... [because] those subclasses capable of reasonable identification require individual notice. This especially holds true in a case such as this one, where those who paid an ETF are entitled to recover the lion’s share of the settlement but are generally unlikely to be current Sprint customers.
(AJA at 4264.) The Court instructed Class Counsel and Sprint to construct a new notice plan that included, inter alia, “an indication from Sprint as to what subclasses of subscribers are reasonably identifiable and a corresponding plan to provide individual notice to those subscribers.” 11 (AJA at 4274.) Because the Court “found notice to be insufficient,” it concluded that it “lack[ed] jurisdiction over the absent class members,” and, “[u]ntil notice [was] properly administered,” it could not “evaluate the reasonableness of the settlement.” (AJA at 4276.)
*1182. Amended Notice Plan
In response to the District Court’s April 30, 2009 opinion and order, Sprint and Class Counsel submitted a proposed Amended Notice Plan (“ANP”) on May 21, 2009.12 Although it addressed several of the concerns that the Court had with the INP,13 the proposed ANP stated that it would be unreasonable to search any of Sprint’s billing records to identify subclasses of individuals who had been charged a flat-rate ETF. To support that contention, Sprint and Class Counsel attached as an exhibit to the proposed ANP a declaration from Sprint’s Vice President of Customer Billing Services, Scott Rice (the “Rice Declaration”). The Rice Declaration detailed the efforts that would be required to search Sprint’s billing records for class members who were charged a flat-rate ETF. Specifically, it noted that, “without unforeseen interruptions or data losses” (AJA at 5504), it would take one to two months to capture information for class members who were charged a flat-rate ETF between April 1, 2009 and June 30, 2009, at an estimated cost of $20,000, and it would take four to five months to capture information for class members who were charged a flat-rate ETF between April 1, 2007 to March 31, 2009, at an estimated cost of $80,000. Because, in the view of Sprint and Class Counsel, “such efforts would require an unreasonable amount of time at a substantial cost,” the ANP they proposed did not provide for any search of Sprint’s billing records.14 (AJA at 4337.)
Twelve days later, on June 2, 2009, the District Court entered an order approving the ANP. The Court explained that it was “satisfied — upon examining [the Rice Declaration] — that it would be unreasonable to require Sprint to engage in further efforts to individually identify additional class members [because] [t]he time, cost, and effort associated with poring through and analyzing the various Sprint databases [were] not reasonable.” (AJA at 4347.) Therefore, the Court found “that individual notice, as outlined [in the ANP], [was] sufficient to satisfy Rule 23.” (Id.) The District Court set the second final approval hearing (the “Second Fairness Hearing”) for October 21, 2009, and set October 7, 2009 as the “[deadline for any member of the settlement class ... to file specific objections to the settlement.” (Id.)
3. Second Fairness Hearing
The Galleguillos Objectors submitted a brief on the October 7, 2009 deadline, arguing, among other things, that the ANP was inadequate under Rule 23(c)(2)(B) and that the Class Representatives themselves *119were inadequate to satisfy the requirements of Rule 23(a).15 With respect to the ANP, the Galleguillos Objectors said that Sprint wrongly failed to provide individual notice to 9.2 million reasonably identifiable class members who had been charged flat-rate ETFs between April 1, 2007 and June 30, 2009. With respect to the Class Representatives, they asserted that the interests of class members who were current Sprint customers were not adequately protected because the Class Representatives “[had] no interest in stopping [the flat-rate ETF] charges because, as former customers, they [were] no longer subject to them.” (AJA at 5554.)
On October 14, Sprint submitted a memorandum in response to the objections related to the adequacy of notice.16 It contended that the 9.2 million number cited by the Galleguillos Objectors was overstated because the Sprint document on which that number was based included flat-rate ETFs charged to government and corporate accounts as well as individual accounts. Athough Sprint acknowledged “that the number of Settlement Class Members who were charged an ETF could measure into the tens of millions,” and a search of its billing records “could result in the identification of millions of Settlement Class Members,” Sprint argued that the Court had already “properly concluded that the effort to identify [those] Settlement Class Members would not be reasonable.” (AJA at 4706.) On October 19, two days before the Second Fairness Hearing, the Galleguillos Objectors conceded that the 9.2 million number was overstated and submitted the testimony of an expert who examined Sprint’s databases from the Ayyad case to provide a corrected estimate. That expert indicated that, using “a widely available statistical software package” (AJA at 5625), he was able to quickly sort the data to find that 44.95% of the customers from those databases were individual accounts. Therefore, the Galleguillos Objectors revised their initial figure of 9.2 million individual class members to 4.2 million.17
The Second Fairness Hearing went forward as scheduled on October 21, 2009.
4. Order Approving Class Certification and Settlement
In an opinion dated January 15, 2010, the District Court overruled all objections,18 certified the proposed settle*120ment class, and approved the Settlement Agreement. Regarding adequacy of representation under Rule 23(a)(4), the District Court stated that two factors must be considered: “(1) the plaintiffs attorney must be qualified, experienced, and generally able to conduct the proposed litigation, and (2) the plaintiff must not have interests antagonistic to those of the class.” (AJA at 10-11 (quoting In re Prudential Ins. Co. of Am. Sales Practices Litig., 962 F.Supp. 450, 519 (D.N.J.1997)).) The Court noted that “[n]o objection has been lodged specifically as to the qualification and capabilities of Class Counsel,” and it also determined that the “interests [of the Class Representatives] [were] not antagonistic to those of other members of the Class.” (AJA at 11.) Acknowledging the Galleguillos Objectors’ contention that the Class Representatives were not adequate because none of them were current subscribers subject to a flat-rate ETF and thus did not negotiate or attempt to enjoin Sprint from enforcing its flat-rate ETF against current customers, the Court said that, if current subscribers who were subject to a flat-rate ETF were “otherwise harmed because of the existence of the flat-rate ETF, such Class members would fall into Category IV ... and would be entitled to the relief afforded therein.”19 (AJA at 12.) The Court further noted that the type of injunctive relief that the Galleguillos Objectors sought — allowing current subscribers to terminate without paying a *121flat-rate ETF- — -“could potentially expose such Class members to a counterclaim for damages from Sprint.”20 (AJA at 12 (citing Garrett v. Coast & S. Fed. Sav. & Loan Ass’n, 9 Cal.3d 731, 108 Cal.Rptr. 845, 511 P.2d 1197, 1203-04 (1973)) (“We do not hold herein that merely because the late charge provision is void and thus cannot be used in determining the lender’s damages, the borrower escapes unscathed. He remains liable for the actual damages resulting from his default.”).)
The District Court then addressed the Galleguillos Objectors’ notice-related claims. Concerning the reach of individual notice, the District Court rejected the contention that Sprint failed to provide notice to 9.2 million identifiable class members.21 The Court said that the “crux” of that objection was “that Sprint could have identified millions of additional class members through Sprint’s own billing records.” (AJA at 22.) The response was that “[ejven if such speculation were correct, the Court ha[d] already examined the Rice Declaration and found that the time, cost and effort necessary to do so ... would be unreasonable in light of all the circumstances.” 22 (Id.)
The Court concluded that it was “satisfied that it would be unreasonable to require Sprint to engage in further efforts to identify class members beyond” the approximately 285,000 additional individuals who received individual notice of the settlement for the first time through the ANP. (AJA at 26.) The Court noted that, just prior to the ANP, only 12,501 claim forms for 19,105 lines of service had been submitted. Since the implementation of the ANP, however, an additional 44,408 claim forms for 66,913 lines of service had been submitted. Because the Court viewed the notice plan as “robust, thorough, and including] all of the essential elements to properly apprise absent Class members of their rights,” it concluded that the “parties ha[d] now fully complied with the stringent requirements set forth by Rules 23(c)(2)(B) and 23(e).”23 (AJA at 26-27.)
The Court entered a final order certifying the proposed settlement class under Rule 23(a) and 23(b)(3) and granting final *122approval to the Settlement Agreement. Appellants then timely filed the present appeals.
II. Discussion24
The Galleguillos Objectors renew on appeal many of the objections they made before the District Court, asserting, among other things, that the District Court abused its discretion by finding that it would be unreasonable to require Sprint to perform any search of its billing records to provide individual notice to class members who had been charged a flat-rate ETF, and that the Court further abused its discretion by holding that the Class Representatives were adequate. Our disposition of these appeals focuses on the first of those issues, though we think the second warrants comment as well.
As the framing of the objectors’ arguments indicates, we review a district court’s decision to certify a class and approve a settlement for an abuse of discretion. In re Pet Food Prods. Liab. Litig., 629 F.3d 333, 341 (3d Cir.2010) (citation omitted). An abuse exists “where the district court’s decision rests upon a clearly erroneous finding of fact, an errant conclusion of law or an improper application of law to fact.” Id. (citation and internal quotation marks omitted).
A. Billing Records Search
The Rice Declaration was the sole basis on which the District Court determined that it would be unreasonable for Sprint to search its billing records to identify class members who had been charged a flat-rate ETF. Even accepting the contents of the Rice Declaration,25 the Galleguillos Objectors claim that the District Court failed to properly exercise its discretion when it determined that it would be unreasonable to require any such search of those records for the purpose of providing individual notice to those class members. We agree.
The Rice Declaration estimated that, to capture contact information for class members who were charged a flat-rate ETF between April 1, 2007 and June 30, 2009, a search would take approximately four to five months at an estimated cost of $100,000.26 Sprint candidly acknowledged *123before the District Court, and likewise represents to us,27 that the search efforts described in the Rice Declaration could result in the identification of millions of class members. After examining the Rice Declaration, however, the District Court, both in its order approving the ANP and in its opinion approving the final settlement, concluded that it would be unreasonable for Sprint to undertake the search of its billing records because of the “time, cost and effort necessary to do so.” (AJA at 22; see also AJA at 4347 (“The time, cost, and effort associated with poring through and analyzing the various Sprint databases are not reasonable....”).) Given the requirements of Rule 23(c) and of our precedents, and in light of the record before the District Court, that decision cannot stand.
As noted earlier, Rule 23(c)(2)(B) requires “individual notice to all members who can be identified through reasonable effort.” Fed.R.Civ.P. 23(c)(2)(B). The Supreme Court discussed what constitutes “reasonable effort” in Eisen v. Carlisle & Jacquelin, which involved a prospective class consisting of nearly six million individuals who had engaged in odd-lot stock purchases. 417 U.S. 156, 166, 94 S.Ct. 2140, 40 L.Ed.2d 732 (1974). The district court in that case had noted that at least two million of those individuals could be identified by names and addresses “[b]y comparing the records and tapes of the odd-lot firms with the wire firm tapes which contain the name and address of each customer,” Eisen v. Carlisle & Jacquelin, 52 F.R.D. 253, 257 (S.D.N.Y.1971), rev’d, 479 F.2d 1005, 1020 (2d Cir.1973), aff'd, 417 U.S. 156, 94 S.Ct. 2140, 40 L.Ed.2d 732 (1974), and that “an additional 250,000 persons who had participated in special investment programs involving odd-lot trading” could also be reasonably identified, 417 U.S. at 166-67, 94 S.Ct. 2140. Including the price of first class postage, the district court determined that individual notice to all identifiable class members would cost $225,000. Id. at 167, 94 S.Ct. 2140. It held, however, that such a substantial expenditure was not required at the outset of the litigation, and ordered limited individual notice, 90% of the cost to be paid by petitioner. Id. The United States Court of Appeals for the Second Circuit reversed, holding that Rule 23(c)(2) required individual notice to all identifiable class members, with the entire cost to be paid by petitioner as the representative plaintiff. Id. at 169, 94 S.Ct. 2140.
The Supreme Court agreed with the Second Circuit and said that “the names and addresses of 2,250,000 class members [were] easily ascertainable, and there [was] nothing to show that individual notice [could not] be mailed to each.” Id. at 175, 94 S.Ct. 2140. The Court expressly rejected petitioner’s argument that the requirement of individual notice should be “dispense[d] with ... in this case ... [because of] the prohibitively high cost of providing individual notice to 2,250,000 class members.” Id. As the Court put it, “individual notice to identifiable class members is not a discretionary consideration to be waived in a particular case. It is, rather, an unambiguous requirement of Rule 23____Accordingly, each class mem*124ber who can be identified through reasonable effort must be notified____” Id. at 176, 94 S.Ct. 2140. The Court noted that “[t]here is nothing in Rule 23 to suggest that the notice requirements can be tailored to fit the pocketbooks of particular plaintiffs.” Id. And the Court also stated that notice by publication “had long been recognized as a poor substitute for actual notice.” Id. at 175, 94 S.Ct. 2140 (citation omitted). Thus, Eisen stands for the proposition that individual notice must be delivered to class members who can be reasonably identified, and that the costs required to actually deliver notice should not easily cause a court to permit the less satisfactory substitute of notice by publication.
In Oppenheimer Fund, Inc. v. Sanders, the Supreme Court again had occasion to consider the individual notice requirement. 437 U.S. 340, 98 S.Ct. 2380, 57 L.Ed.2d 253 (1978). To identify class members in Oppenheimer Fund, the representative plaintiffs sought to require the defendants, an investment fund, its management corporation, and a brokerage firm, to help compile a list of names and addresses of class members from records kept by the transfer agent for one of the defendants, so that the individual notice required by Rule 23(c)(2) could be sent. 437 U.S. at 342, 98 S.Ct. 2380. The class was estimated to include approximately 121,000 persons. Id. at 344-45, 98 S.Ct. 2380. The transfer agent’s employees testified that:
[I]n order to compile a list of the class members’ names and addresses, they would have to sort manually through a considerable volume of paper records, keypunch between 150,000 and 300,000 computer cards, and create eight new computer programs for use with records kept on computer tapes that either [were] in existence or would have to be created from the paper records.
Id. at 345, 98 S.Ct. 2380. “The cost of [those] operations was estimated in 1973 to exceed $16,000.”28 Id. Having learned of the cost and efforts required, the representative plaintiffs sought to redefine the class to include only persons who had bought fund shares during a specific time period and still held shares in the fund, so that individual notice could be sent in one of the fund’s periodic mailings to its current shareholders. Id. That redefinition would have had the effect of excluding individual notice to 18,000 former fund shareholders who were class members, and reaching 68,000 current shareholders who were not class members. Id. The district court rejected the proposed redefinition because it arbitrarily reduced individual notice to the class. Id. at 346, 98 S.Ct. 2380. The district court explained that “it [was] the responsibility of defendants to cull out from their records a list of all class members and provide [that] list to plaintiffs.” Id. (citation and internal quotation marks omitted). The district court also held that the cost of that endeavor was “the responsibility of [the] defendants,” though it did note that the representative plaintiffs would “then have the responsibility to prepare the necessary notice and mail it at their expense.” Id. (citation and internal quotation marks omitted).
*125The Second Circuit, en banc, affirmed, id. at 347-48, 98 S.Ct. 2380, and the Supreme Court granted certiorari on the underlying cost-allocation problem, id. at 349, 98 S.Ct. 2380. Although the Supreme Court held that the district court abused its discretion in requiring defendants to bear the expenses of identifying the class members,29 the Court affirmed, sub silentio, the decision requiring the additional search efforts. Id. at 364, 98 S.Ct. 2380. In particular, the Supreme Court concluded that the “information [from the transfer agent] must be obtained to comply with the [representative plaintiffs’] obligation to provide notice to their class.” Id.
In the course of discussing the underlying cost-allocation issue, the Oppenheimer Fund court relied heavily on the decision of the United States Court of Appeals for the Fifth Circuit in In re Nissan Motor Corp. Antitrust Litigation, 552 F.2d 1088 (5th Cir.1977). See Oppenheimer Fund, 437 U.S. at 355-60, 98 S.Ct. 2380. The Fifth Circuit there discussed Rule 23(e)(2)’s individual notice requirement in the context of identifying a class of original retail purchasers of 371,000 new Datsun cars. The plaintiffs in Nissan had argued to the district court that the defendants, including Nissan Motor Corp. and every Datsun dealer nationwide, were “obligated to conduct and bear the costs of an examination of 1.7 million Retail Delivery Report (“RDR”) cards that recorded sales of new Datsun motor vehicles between 1966 and 1975 so that individual notice could be sent to class members. 552 F.2d at 1094. The district court instead only ordered the defendants, at their own expense, to prepare and submit a computer listing containing the names and addresses of currently registered Datsun owners, id., “characterize[ing] the examination of the 1,700,000 RDR cards to extract the class members’ names and addresses as an ‘herculean task’ and an ‘unnecessarily time consuming and burdensome process,’ ” id. at 1096.
The Fifth Circuit, however, vacated the district court’s class notice order, explaining:
The source or sources providing the greatest number of names and addresses must be used. Obviously, the word “reasonable” cannot be ignored. In every case, reasonableness is a function of anticipated results, costs, and amount involved. A burdensome search through records that may prove not to contain any of the information sought clearly should not be required. On the other hand, a search, even though calculated to reveal partial information or identification, may be omitted only if its cost will exceed the anticipated benefits. Here, we know that the RDR cards provide the court with the best available listing of the names and addresses of all class members. Indeed, the parties agree on this. They only shy from undertaking the effort. While the search cannot be made with push-button ease, its advantages bring the effort required within the range of reasonableness.
Id. at 1098-99. The Nissan court then expounded on reasonableness:
When the chore of examining defendants’ RDR cards is juxtaposed to the efforts required to identify the ... class members [in Eisen v. Carlisle & Jacqueline, it pales by comparison. The district court’s characterization of the undertaking here as “herculean” is accurate only in relation to the class’s size. *126The key, though, is reasonable effort, and a large class requires a large effort. Subdivision (c)(2) mandates that each class member be given the “best notice practicable under the circumstances.” While the mechanical process of examining the cards may prove to be expensive and time-consuming, the individual right of absentee class members to due process makes the cost and effort reasonable.
Id. at 1100. Such effort was required because “[ajbsentee class members ... generally have ... no knowledge of the suit until they receive initial class notice [,and individual notice] will be their primary, if not exclusive, source of information for deciding how to exercise their rights under [R]ule 23.” Id. at 1104. Accordingly, the Fifth Circuit ordered the district court “to require individual notice to the class based on the information available on the RDR cards.” Id. at 1100.
We have been similarly stringent in enforcing the individual notice requirement. In Greenfield v. Villager Industries, Inc., we vacated a district court’s order approving a settlement because no effort was made to identify class members from the defendant’s stock transfer records for the purpose of giving individual notice; rather, only publication notice was used. 483 F.2d 824, 834 (3d Cir.1973). We said that “a procedure such as the class action, which has a formidable, if not irretrievable, effect on substantive rights, can comport with constitutional standards of due process only if there is a maximum opportunity for notice to the absentee class member.... ” Id. at 831. Citing Supreme Court precedent, we noted that publication notice “failed to satisfy due process requirements since ‘... it [was] not reasonably calculated to reach those who could be informed by other means at hand.’ ” Id. at 832 (quoting Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 319, 70 S.Ct. 652, 94 L.Ed. 865 (1950)). We explained that, “[w]here names and addresses of members of the class are easily ascertainable, ... due process would dictate that the ‘best notice practicable under the circumstances ... ’ would be individual notice.” Id. at 832 (quoting Fed.R.Civ.P. 23(c)(2)). Our holding, based on Eisen, was straightforward: “ ‘[a]ctual notice must be given to those whose identity could be ascertained with reasonable effort.’” Id. (quoting Eisen, 479 F.2d at 1009, aff'd 417 U.S. 156, 94 S.Ct. 2140). We also said that it was “[t]he ultimate responsibility” of the district court to ensure that the parties complied with notice requirements because “the district court [is] ... the guardian of the rights of the absentees.” Id.
Those cases notwithstanding, Sprint cites a decision from the Northern District of Georgia, In re Domestic Air Transportation Antitrust Litigation, to support its claim that it would be unreasonable to require it to search its billing records so that individual notice can be sent to more people. 141 F.R.D. 534 (N.D.Ga.1992). Domestic Air involved a class action on behalf of purchasers of “domestic airline passenger tickets from one or more of the defendant airlines ... to and/or from a defendant’s hub.” Id. at 537. Initially, the defendants had argued to the Court that class members could not be identified from the airlines’ records for the purposes of compiling a list to provide those members with individual notice. Id. at 539. After the Court certified the class, an evidentiary hearing was held regarding “the proposed content, timing, and method of notice.” Id. at 538. At that hearing, the plaintiffs agreed with the defendants’ initial position “that class members ... [could not] be identified with reasonable effort and thus there [was] no list of class members to which mandatory individual notice [could] be given.” Id. The defen*127dants, however, in an abrupt “about face,” id. at 540, then “insist[ed] that it [was] possible to identify a partial list of class members, and plaintiffs must, therefore, individually notify persons on the partial list,” id. at 538. In support, the defendants said they had developed a list containing more than 9.3 million names and addresses of possible class members. Id. at 541.
The district court took a different view. It determined that the list developed by the defendants was not a list of class members, and it found “as a fact that class members [could not] be identified at [that] time through reasonable effort.” Id. at 541. As the district court saw it, the defendants’ list was both over-inclusive and under-inclusive, and it was thus “ ‘impossible to estimate how many absentee class members would receive individual notice.’ ” Id. at 545 (quoting Nissan, 552 F.2d at 1099). Cautioning that “ ‘reasonableness is a function of anticipated results, costs, and amounts involved,’ ” id. at 547 (quoting Nissan, 552 F.2d at 1099), the court concluded that
this [was] not the classic case where Rule 23(c)(2) individual notice [was] mandated. In cases such as Eisen and Nissan the records kept by the defendants indisputably contained the names and addresses of the universe of class members.... Because the [list at issue in Domestic Air ] [was] not a list of class members, there [was] no way to assure that notice to the list would definitely result in notice to a substantial number of class members.
Id. at 546. Thus, the district court did “not direct individual mail notice ... to the ... list.” Id.
The decision in Domestic Air is no support for Sprint here. On the contrary, as the District Court in this action had initially noted in its order holding the INP deficient, “Domestic Air does not stand for the proposition that partial class lists do not require individual notice; rather, it adopted quite the opposite formulation. Partial lists — to the extent they are accurate — would require 23(e)(2)-compliant notice.” (AJA at 4262.) After relying on both Eisen, (see AJA at 4263 (“Given that Eisen required notice to a partial class and that it pronounced constructive notice to be especially unreliable, this Court is hard-pressed to find Sprint’s arguments persuasive.”)), and Nissan, (see AJA at 4263 (“Nor does the fact that a large effort is required to identify a subset of class members automatically render individual notice inapplicable.” (citing Nissan, 552 F.2d at 1100))), the District Court found
that Sprint must do more than it ha[d] done so far. The fact that not every member of the class can receive the best notice does not mean that everyone gets the least notice. Rather, those subclasses capable of reasonable identification require individual notice. This especially holds true in a case such as this one, where those who paid an ETF are entitled to recover the lion’s share of the settlement but are generally unlikely to be current Sprint customers. Sprint shall attempt to identify subclasses of individuals and include individual notice to those persons.
(AJA at 4264 (emphasis added).)
Despite that well-grounded and thoroughly persuasive conclusion, the District Court, much like the defendants in Domestic Air, did something of an about face when it approved the ANP proposed by Sprint and Class Counsel. Other than a general reference to the Rice Declaration for the proposition that the “time, cost, and effort necessary to [conduct a partial search of its billing records to provide individual notice to a subset of class members who were charged ETFs] ... would *128be unreasonable in light of all the circumstances” (AJA at 22), the Court did not provide any support for its new and very different determination that Sprint did not need to conduct a search of its billing records to provide individual notice to a larger group of class members. This is particularly puzzling given that the District Court had said, in its order holding the INP deficient, that “Sprint can run targeted searches that pull relevant information for sub-classes of individuals.” (AJA at 4260 (emphasis added).)
Viewing “reasonableness [as] a function of anticipated results, costs, and amount involved,” Nissan, 552 F.2d at 1099, the District Court’s changed determination, based solely on the Rice Declaration, that it would be unreasonable for Sprint to undertake any search of its own billing records was “an errant conclusion of law or an improper application of law to fact.” In re Pet Food Prods. Liab. Litig., 629 F.3d at 341 (citation and internal quotation marks omitted). Similar to Eisen, where at least 2.25 million class members could have been identified by names and addresses, Sprint has acknowledged here that the database search outlined in the Rice Declaration “could result in the identification of millions of Settlement Class Members.”30 (AJA at 4706.) The cost of identifying those “millions” of class members is approximately $100,000. If only two million people were identified through that billing records search, the search would have cost approximately 5 cents per class member identified in 2009. Including the expense of mailing the individual notice, the cost would have been approximately 43 cents per class member.31 Given the size of the class and the due process rights at stake, these are not troublingly high sums.
Even if the costs had been higher, however, that would not automatically mean they were unreasonable. Eisen expressly rejected the argument that costs are the primary driver in the judgment on notice, because “individual notice to identifiable class members is not a discretionary consideration to be waived in a particular case. It is, rather, an unambiguous requirement of Rule 23.... ” 417 U.S. at 176, 94 S.Ct. 2140. Here, the costs per class member were projected to be less than the per-member cost for individual notice in both Eisen and Oppenheimer Fund, after adjusting for inflation.32
*129Sprint refers to the “cumbersome process required to search its vast data environments” (Sprint’s Br. at 35) and argues that “[e]ven assuming that the efforts outlined in the Rice Declaration would yield 4.2 million ... [c]lass members, it is simply another way of restating the already known [fact that,] with significant effort, a large number of ... [c]lass members could be identified,” (Sprint’s Br. at 37-38). Instead, Sprint asserts that “[t]he question before the District Court ... was whether that effort was reasonable,” and “the Court reviewed the efforts outlined in the Rice Declaration and determined, within its sound discretion, that it would be unreasonable to have Sprint undertake those efforts.” (Sprint’s Br. at 38.) But, if the efforts detailed in the Rice Declaration, whereby a computer program would have to run search queries in certain databases, would identify 4.2 million class members, we fail to see why running those search inquiries is unreasonable, and no explanation for that conclusion was provided by the District Court. In fact, the effort that would be required here seems less significant than the efforts required in Eisen, 52 F.R.D. at 257 (identifying at least two million individuals “[b]y comparing the records and tapes of the odd-lot firms with the wire firm tapes which contain the name and address of each customer”), or in Oppenheimer Fund, 437 U.S. at 345, 98 S.Ct. 2380 (requiring transfer agent’s employees to “sort manually through a considerable volume of paper records, keypunch between 150,000 and 300,000 computer cards, and create eight new computer programs for use with records kept on computer tapes that either [were] in existence or would have to be created from the paper records.”), or in Nissan, 552 F.2d at 1094, 1096 (undertaking examination of 1.7 million RDR cards to identify names and addresses of 371,000 original retail purchasers, an examination that the district court called “herculean” and “unnecessarily time consuming and burdensome”).
As did the parties in Nissan, it appears that Sprint and the Class Representatives would agree that the search of the billing records would “provide ... the best available listing of the names and addresses of ... class members [who were charged ETFs].... They only shy away from undertaking the effort.” Id. at 1099. While it may be that a search of the billing records to find class members who have been charged flat-rate ETFs “cannot be made with push-button ease,” “its advantages,” based on the admissions made by Sprint itself, appear likely to “bring the effort required within the range of reasonableness.” Id. Because we have no way of knowing what in the Rice Declaration caused the District Court to change its mind about the need for a search of the billing records, “the individual right of absentee class members to due process” under Rule 23(c)(2) may have been violated. Id. at 1100. In light of the principles outlined in Eisen, Oppenheimer Fund, and Nissan, and our own precedent calling for “a maximum opportunity for notice to the absentee class member,” Greenfield, 483 F.2d at 831; see Girsh v. Jepson, 521 F.2d 153, 159 (3d Cir.1975) (noting our “Circuit’s strong policy in favor of ‘maximum *130notice’ ”), the District Court needs to do more to fulfill its duty as “the guardian of the rights of the absentees” to ensure that the parties complied with the individual notice requirement of Rule 23(c)(2), Greenfield, 483 F.2d at 832.
We will therefore remand to the District Court to again assess whether the ANP passes muster under Rule 23(c)(2). Given Sprint’s concession that a billing records search could result in identifying millions of class members who were charged a flat-rate ETF — individuals who are in the sweet spot of the proposed class — we are not sure how it can be said that it is unreasonable for Sprint to search any of its billing records, but we leave that determination to the District Court, to be made on a more complete record and with a fuller explanation. In that connection, we note the availability of statistical sampling of Sprint’s billing records as a means to provide the District Court with a better grounded estimate of the number of class members who could, through a search of those records, be identified during the relevant period.33 Once that estimate is made, the Court, weighing the “anticipated results, costs, and amount involved,” Nissan, 552 F.2d at 1099, should be able to *131determine whether a full search of the subject period would be reasonable, especially in light of the fact that the class members who were charged a flat-rate ETF were the ones who were “entitled to recover the lion’s share of the settlement” (AJA at 4264) but were unlikely to otherwise know of it. See Nissan, 552 F.2d at 1104 (“Absentee class members will generally have had no knowledge of [a] suit until they receive the initial class notice[, which] will be their primary, if not exclusive, source of information.... ”).
B. Adequacy of Representatives
Although we remand to the District Court to further address the notice issues, we also suggest that the Court consider again whether the Class Representatives can adequately represent all class members. The Galleguillos Objectors allege that the Class Representatives are inadequate since none of them were “current subscribers subject to Sprint’s illegal ETFs” at the time that the Settlement Agreement was executed. (Galleguillos Objectors’ Opening Br. at 59.) One of the essential problems with the settlement, as those objectors see it, is “the license it grants to Sprint to continue making illegal ETF charges against current subscribers.” (Id. at 60.) According to the Galleguillos Objectors, because “[t]he claims of the class representatives are ... atypical of the claims.... of [current subscribers,] ... the class representatives are inadequate representatives.” (Id.) Sprint responds that the Class Representatives satisfy the adequacy requirement of Rule 23(a)(4) because their interests “[were] not antagonistic to those of the class.”34 (Sprint’s Br. at 22 (citations and internal quotation marks omitted).)
As noted earlier, Rule 23(a)(4) provides that, in order to certify a class, a court must find that “the representative parties will fairly and adequately protect the interests of the class.” Fed.R.Civ.P. 23(a)(4). “The adequacy inquiry under Rule 23(a)(4) serves to uncover conflicts of interest between named parties and the *132class they seek to represent.” Amchem Prods., Inc. v. Windsor, 521 U.S. 591, 625, 117 S.Ct. 2231, 138 L.Ed.2d 689 (1997). More specifically, as we stated in In re Community Bank of Northern Virginia, the inquiry has two purposes: “to determine [1] that the putative named plaintiff has the ability and the incentive to represent the claims of the class vigorously, ... and [2] that there is no conflict between the individual’s claims and those asserted on behalf of the class.”35 622 F.3d 275, 291 (3d Cir.2010) (ellipsis in original) (quoting Hassine v. Jeffes, 846 F.2d 169, 179 (3d Cir.1988)). “This inquiry is vital, as ‘class members with divergent or conflicting interests [from the named plaintiffs and class counsel] cannot be adequately represented....’” Id. at 291-92 (alteration in original) (quoting In re Diet Drugs Prods. Liab. Litig., 385 F.3d 386, 395 (3d Cir.2004)).
In its opinion approving the settlement here, the District Court focused on the second purpose of the Community Bank inquiry as to Rule 23(a)(4), i.e., the “no conflict” part.36 The Court stated that “ ‘the plaintiff must not have interests antagonistic to those of the class,’ ” (AJA at 11 (quoting In re Prudential Ins. Co. of Am. Sales Practices Litig., 962 F.Supp. 450 (D.N.J.1997))), and it found that the Class Representatives did not.
If that were the complete test, we would perhaps be less concerned about the District Court’s finding of adequacy under Rule 23(a)(4), but the test cited by the District Court fails to include the first and, in this instance,37 likely the most important part of the Community Bank inquiry. That part requires that the Class Representatives have “the ability and the incentive to represent the claims of the class vigorously.” In re Cmty. Bank of N. Va., 622 F.3d at 291 (citation omitted). Here, it is difficult to understand how the Class Representatives, none of whom were Sprint customers at the time that the Settlement Agreement was executed, had the *133interest, much less the incentive, to stop Sprint from enforcing flat-rate ETFs against its current customers. Cf id. at 311 (vacating decision to certify class “because the settlement appeared] to lack ‘structural assurance of fair and adequate representation for the diverse groups and individuals affected’ ” (quoting Amchem, 521 U.S. at 627, 117 S.Ct. 2231)); Nat’l Super Spuds, Inc. v. N.Y. Mercantile Exch., 660 F.2d 9, 17 n. 6 (2d Cir. 1981) (“Th[e] justification for permitting the representatives to sue on behalf of the class has no application to claims of class members in which the representatives have no interest and which ... they are willing to throw to the winds in order to settle their own claims.”).
The District Court rejected the objectors’ adequacy of representation argument, in part,38 because it found that, even if class members who were subscribers at the time that the Settlement Agreement was executed were still subject to a flat-rate ETF, those members would be entitled to the relief afforded under Category IV of the Settlement Agreement. We briefly note, however, the dissimilar treatment received by class members who only qualified for benefits under Category IV, but who were similarly situated to class members who qualified for benefits either under Category I (charged and paid a flat-rate ETF) or Category II (charged but did not pay a flat-rate ETF).39 Those class members who were Sprint customers as of March 15, 2010 — the claim deadline for Categories I and II40 — but terminated their contract between March 15 and December 31, 2010 and were charged a flat-rate ETF,41 only qualified for benefits under Category IV, which provided for certain non-cash relief.42 That relief is far different from the relief that other similarly situated class members were entitled to under Category I or Category II.43 {See *134AJA at 285 (providing a $90 payment to class members under a two year contract who terminated any time between the seventh and twenty-fourth month and paid a flat-rate ETF); AJA at 287-88 (providing a $90 credit to class members under a two year contract who terminated any time between the seventh and twenty-fourth month and were charged, but did not pay, a flat-rate ETF).)
Nevertheless, because that objection was not made before the District Court with the clarity it has been pressed on us,44 we will not opine on the District Court’s conclusion that the Class Representatives can adequately represent all class members. That being said, because the case must be considered again on the notice issue, and because the adequacy issue is one of high significance, we urge the District Court to consider again in greater detail whether the Class Representatives are adequate under Rule 23(a)(4).
III. Conclusion
With full appreciation for the considerable efforts that have been invested in the settlement of this class action, we emphasize again the judicial duty to act as the guardian of absent class members. For the reasons stated, we conclude that that duty was not fully met and, accordingly, vacate the District Court’s January 15, 2010 order and remand the ease for further proceedings consistent with this opinion.