BOSTON – November 27, 2007 – State Street Corporation (NYSE:STT), the world’s leading provider of financial services to institutional investors, today announced the launch of the State Street Private Equity Index^sm. The Index is based on the latest quarterly statistics from State Street Investment Analytics’ Private Edge^® Group, which provides detailed analyses of customers’ private equity portfolios through a fully automated web-enabled environment.

Comprising of data including more than 1,300 private equity partnerships with a total fund size in excess of $1.1 trillion, the State Street Private Equity Index will allow private equity investors to evaluate their performance against their peers across a broad and representative sample of investments. Unlike other indices, the State Street Private Equity Index does not rely on voluntary reporting of cash flows from general partners in order to calculate returns. As a result, the Index provides an accurate representation of private equity holdings across all funds, without any reporting bias.

“The industry has been seeking a more robust source of comparative information for private equity performance and more importantly, peer group analysis,” said William Pryor, senior vice president. “Private equity investors now have a benchmark as well as an additional layer of transparency to analyze their private equity holdings.”

The State Street Private Equity Index includes data derived from the diverse client base of The Private Edge Group covering public and private pensions, endowments and foundations, representing more than 4,000 commitments totaling over $150 billion. The Private Edge Group has one of the most expansive and comprehensive private equity data sets currently maintained, including partnership information down to the portfolio company level.

“The industry has long awaited a third party private equity index based on consistent and reliable data,” said Chris Ailman, chief investment officer of CalSTRS. “ State Street’s index will be a tremendous asset in evaluating our holdings which will provide us the information necessary to make strategic business decisions.”

State Street Investment Analytics (SSIA) services are provided through offices located around the world, including Alameda, Amsterdam, Boston, Dublin, Edinburgh, Frankfurt, Hong Kong, London, Luxemburg, New York, Paris, Sydney, Toronto and Zurich. SSIA calculates performance for over 800 clients globally on asset volumes exceeding $4.5 trillion, providing private equity performance and analytics services through The Private Edge Group since 1994.

The table below summarizes the composition and breadth of the index by major private equity strategy, in addition to the respective long-term internal rates of return (IRR):

State Street Private Equity Index ^sm
Composition as of June 30, 2007

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$15.1 trillion in assets under custody and US$2.0 trillion in assets under management, as of September 30, 2007, 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.

About Private Edge^® Group
State Street 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.