BOSTON – January 31, 2008 – State Street Corporation (NYSE:STT), the world’s leading provider of financial services to institutional investors, today announced the third quarter results 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 allows 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 reporting bias.

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 tightening of credit conditions, especially in the US, has constrained deal flow during the quarter as evidenced by cancellation and postponement of several buyout transactions and increased challenges in placing leveraged buyout debt for completed transactions,” said William Pryor, senior vice president. “This decrease in buyout transactions has manifested itself in slightly lower overall valuations and thereby lower long-term returns on a quarter-over-quarter basis across the US private equity space. However, international private equity actually displayed slightly improved returns over the prior quarter due to the continued weakness of the US dollar.”

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 1200 clients globally on asset volumes exceeding $5.5 trillion, providing private equity performance and analytics services through The Private Edge Group since 1994.

The table below summarizes 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 Index^sm

Composition and Long-term IRR as of September 30, 2007

*Included in total

About State Street
State Street Corporation (NYSE: STT) is the world's leading specialist in providing institutional investors with investment servicing, investment management and investment research and trading services. With $15.30 trillion in assets under custody and $2 trillion in assets under management at December 31, 2007, State Street operates in 26 countries and more than 100 geographic markets worldwide. For more information, visit State Street’s web site 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.