MEMORANDUM AND ORDER
JAMES C. FRANCIS, IV, Magistrate Judge.
Plaintiff Ironshore Insurance Ltd. ("Ironshore") brings this action against defendant Western Asset Management Company ("Western") for breach of contract and breach of fiduciary duty. The parties have exchanged initial and rebuttal expert reports; Ironshore now seeks leave to serve two reply reports to respond to matters Western allegedly raised for the first time in its rebuttal reports and to amend charts attached as exhibits to one of its initial reports. For the reasons that follow, the plaintiff's application is granted in part and denied in part.
On February 21, 2007, Ironshore, a broker-sourced insurance company, and Western, an investment adviser, entered into an Investment Management Agreement (the "IMA"), under which Ironshore granted Western "sole power" over Ironshore's $520 million limited duration fixed income portfolio (the "Portfolio"), subject to the terms of the IMA. (Amended Complaint ("Am. Compl."), §§ 11, 12, 26, 28-29). Western's investment decisions were constrained by the Recommended Limited Duration Fixed Income Investment Guidelines ("Investment Guidelines"), which were incorporated into the IMA. (Am. Compl., § 30). Ironshore alleges that Western breached its contractual and fiduciary duties under the IMA, "[m]ismanaging the Portfolio by... concentrating the Portfolio in impermissibly risky, illiquid, and volatile securities, failing to diversify risk exposures, and ignoring relevant market information." (Am. Compl., §§ 83, 89). Ironshore terminated the IMA on May 20, 2008, after sustaining an unrealized loss of approximately $55.5 million, and by the end of 2008, Ironshore's net realized and unrealized losses exceeded $130 million. (Am. Compl., §§ 71-74).
The parties exchanged discovery pursuant to a Pretrial Scheduling Order issued by the Honorable Laura Taylor Swain, U.S.D.J. (Order dated Nov. 4, 2011 ("Order")). The Order provided for a simultaneous exchange of initial expert reports "on issues as to which [ea]ch party has the burden of proof or otherwise in support of the party's case, " to be followed by "[r]ebuttal disclosures." (Order at 1-2). The Order did not provide for the exchange of reply reports. For Ironshore, David K.A. Mordecai and Daniel I. Castro submitted initial and rebuttal reports; Avram S. Tucker and Erik R. Sirri submitted initial reports for Western, and, along with Keith M. Schappert and Paul Jablansky, submitted rebuttal reports.
Ironshore's experts concluded that Western's construction of the Portfolio exposed Ironshore to undue risks, in violation of Western's contractual and fiduciary duties. (Expert Report of David K.A. Mordecai dated March 1, 2013 ("Mordecai Report") at 9; Expert Report of Daniel I. Castro, Jr. dated March 2, 2013 ("Castro Report") at 10). In particular, the experts assert that (1) Ironshore's business as a property and casualty insurance company dictated construction of a conservative portfolio; (2) despite Ironshore's communication of the desired characteristics to Western, the Portfolio exposed Ironshore to undue credit, extension, and liquidity risks; and (3) the Portfolio, designed to have risk characteristics approximating the Treasury Benchmark, was inadequately diversified and resulted in substantial underperformance relative to the Treasury Benchmark. (Mordecai Report at 9; Castro Report at 10).
In response, Western's experts concluded that Western's construction and management of the Portfolio conformed to industry practice and to Ironshore's objectives stated in the IMA and the Investment Guidelines. In particular, they assert that (1) the risk profile of the Portfolio was consistent with that of investment holdings of other investors similar to Ironshore (Expert Report of Keith M. Schappert dated April 29, 2013 ("Schappert Rebuttal") at 42); (2) the IMA and the Investment Guidelines, rather than the standards used by Ironshore's experts, provide the proper standard to evaluate the Portfolio (Schappert Rebuttal at 12); and (3) Western could not have constructed a less risky portfolio that could have achieved Ironshore's stated objective of outperforming the Treasury Benchmark by 50 points (Schappert Rebuttal at 45-46). Ironshore contends that these arguments are raised for the first time in Western's rebuttal reports and seeks leave to file reply reports to respond to them.
"It is routine that the party with the burden of proof on a particular issue be the first to submit its expert reports addressing the issue. The other party then is given the opportunity to submit a rebuttal report and, if requested and allowed by the Court, a reply expert report may follow." Sandata Technologies, Inc. v. Infocrossing, Inc., Nos. 05 Civ. 9546 , 06 Civ. 1896, 2007 WL 4157163, at *1 (S.D.N.Y. Nov. 16, 2007) (citing Fed.R.Civ.P. 26(a)(2)); accord Lidle v. Cirrus Design Corp., No. 08 Civ. 1253, 2009 WL 4907201, at *4 (S.D.N.Y. Dec. 18, 2009).
Reply expert reports may be appropriate if the rebuttal reports raise new matters not discussed in the initial reports. See Lidle, 2009 WL 4907201, at *4. Such reply reports, if allowed, should be "confined to new matters adduced by the defense and not to repetition of the plaintiff's theory of the case.'" Id . (quoting Brune v. Time Warner Entertainment Co., No. 02 Civ. 5703, 2004 WL 2884611, at *2 (S.D.N.Y. Dec. 14, 2004)). "It is not an opportunity for the correction of any oversights in the plaintiff's case in chief." Crowley v. Chait , 322 F.Supp.2d 530, 551 (D.N.J. 2004) (internal quotation marks and citations omitted). Thus, I turn to whether the defendant's experts raised any new points not discussed in the plaintiff's initial expert reports.
A. Investment Holdings of Other Insurance Companies
Ironshore claims that Western's experts improperly address investment holdings of insurance companies other than Ironshore. (Letter of Thorn Rosenthal dated May 3, 2013 ("Rosenthal Letter") at 3). In their rebuttal reports, Western's experts contend that other similarly-situated insurance companies held the same, similar, or even more risky securities (Schappert Rebuttal at 50-52), and conclude that Ironshore's status as an insurer by itself conveys no information about whether the securities that Western purchased were too risky (Expert Rebuttal Report of Professor Erik R. Sirri dated April 29, 2013 ("Sirri Rebuttal") at 42; Schappert Rebuttal at 42-45).
This is not a new issue. Ironshore's experts concluded in their initial reports that Western purchased securities that were too risky for a property and casualty insurance company such as Ironshore. Dr. Mordecai explained that the nature of the business of property and casualty insurance companies "necessitates more liquid, lower volatility, shorter weighted average life investments." (Mordecai Report at 10-12). And Mr. Castro opined that certain bonds in the Portfolio "were totally unsuitable for a property and casualty insurance company which required safe and liquid investments." (Castro Report at 50).
Western's rebuttal reports were limited to the same subject matters encompassed in Ironshore's initial reports, which included the issue of whether the Portfolio was suitable for Ironshore, given its status as a property and casualty company. See United States v. Casamento , 887 F.2d 1141, 1172 (2d Cir. 1989) ("The function of rebuttal evidence is to explain or rebut evidence offered by the other party."). The rebuttal reports sought to "explain, repel, counteract or disprove the evidence of the adverse party" by pointing to other similarly-situated investors, S.W. v. City of New York, No. 2009 CV 1777, 2011 WL 3038776, at *2 (E.D.N.Y. July 25, 2011) (internal quotation marks omitted), not to present new arguments, see Ebbert v. Nassau County, No. 05 CV 5445, 2008 WL 4443238, at *13 (E.D.N.Y. Sept. 26, ...