State Street has agreed to purchase Goldman Sachs Administration Services (GSAS), a leading hedge fund administrator, from the Goldman Sachs Group, in a cash transaction of $550m, subject to certain adjustments.

The takeover of GSAS will place State Street as the leading hedge fund administrator globally, the acquirer said.

The transition is expected to complete by the first week of the fourth quarter of 2012, after obtaining regulatory approvals and satisfying other customary closing conditions.

As per the merger deal struck, GSAS employees, including client-facing staff and the management team will be absorbed by State Street, however, the deal does not include Goldman Sachs’ Prime Brokerage business, which remains an important offering of Goldman Sachs.

GSAS manages nearly $200bn in single manager hedge fund assets on behalf of almost 150 investment manager clients globally, said the US wealth manager.

State Street, with a dedicated team of 3,000 professionals offers a wide variety of middle office, fund administration, risk analytics and credit services to hedge funds, private equity funds, real estate funds and institutional investors.

As of 30 June 2012, State Street had $22.4 trillion in assets under custody and administration and $1.9 trillion in assets under management and the firm trades in 29 countries and more than 100 geographic markets.