STT State Street Corporation

State Street Corporation (NYSE: STT), the world�s leading provider of financial services to institutional investors, announced today the results of the State Street Private Equity Indexsm as of December 31, 2007. The index is based on the latest quarterly statistics from State Street Investment Analytics� Private Edge� Group. The Private Edge� Group provides detailed analyses of private equity investments for a diverse client base covering public and private pensions, endowments and foundations, representing more than 4,000 commitments totaling more than $160 billion. The Private Edge� Group has one of the most extensive and comprehensive private equity data sets currently maintained in the marketplace, including partnership information down to the portfolio company level. State Street Investment Analytics provides performance and analytics services through 14 offices located around the world. It provides services for more than 1,200 clients globally on asset volumes exceeding $5.5 trillion in assets. The following tables below depict the quarter-over-quarter internal rates of return (IRR) of the index, the end-to-end IRRs for the index across 1, 3, 5 and 10-year horizons as of December 31, 2007, and the long-term internal rates of return (IRR) of the index by major private equity strategy, in addition to the composition of the index: State Street Private Equity Indexsm Composition and long-term IRR as of December 31, 2007 � � � Strategy � Number of Funds � Commitments ($B) � Long-term IRR% Buyout � 634 � 852.0 � 15.9 Venture Capital � 614 � 206.4 � 12.8 Other � 173 � 146.8 � 13.8 Total � 1,421 � 1,205.2 � 15.2 US only � 1,175 � 942.1 � 14.2 International only � 246 � 263.1 � 21.2 �Mega buyout funds continue to deliver higher since-inception IRRs as a whole than their smaller peers and other segments, such as venture capital,� said Gerard J. Labonte, vice president, State Street Corp. �Investors with access to the largest buyout managers have fared quite well against the rest of the asset class and in comparison to public market equivalents.� Considering the late 2007 credit crunch and corresponding slowdown in exits, Labonte continued. �The asset class saw continued pressure on valuations and exits, especially in domestic markets. However, continued US dollar weakness partially offset this effect for those invested in overseas opportunities.� About State Street Investment Analytics State Street Investment Analytics (SSIA) provides private equity performance and analytics services through The Private Edge� Group, which it has offered for more than a decade. The Private Edge� Group provides detailed analyses of customers� private equity portfolios through a fully automated web-enabled environment and offers services ranging from performance measurement to complex quantitative and qualitative portfolio analysis. SSIA provides client services from 14 offices around the world, including Alameda, Amsterdam, Boston, Dublin, Edinburgh, Frankfurt, Hong Kong, London, Luxembourg, New York, Paris, Sydney, Toronto and Zurich. About State Street State Street Corporation (NYSE: STT) is the world's leading provider of financial services to institutional investors, including investment servicing, investment management, and investment research and trading. With US$15 trillion in assets under custody and US$2 trillion in assets under management as of March 31, 2008, State Street operates in 26 countries and more than 100 geographic markets worldwide. For more information, visit State Street's website at www.statestreet.com.