Blackstone Group LP, the world’s biggest alternative-asset manager, gathered $15.8 billion for the largest fund to invest in global real estate.

The firm collected more than 90 percent of the pool, its eighth fund for global property, from institutions in about four months, a person with knowledge of the matter said in March. The remainder was raised from individual investors, a process that takes longer to complete because of the paperwork involved, the person said.

Blackstone has already committed 20 percent of the fund to deals, according to a statement. The New York-based firm in April agreed to a $14 billion transaction to buy real estate assets being divested by General Electric Co., and last month agreed to buy Strategic Hotels & Resorts Inc., the manager of properties including Manhattan’s Essex House and the Ritz-Carlton Half Moon Bay, for about $3.9 billion.

Blackstone has built the largest real estate investing business, overseeing $92 billion in assets as of June 30. Its seven previous global property funds have doubled their invested capital, with annualized returns of 18 percent after fees since 1994, according to the firm’s most recent earnings statement.

The real estate group is led by Jon Gray, 45, considered a possible successor to Chief Executive Officer Steve Schwarzman. Gray’s group also manages an $8.2 billion fund investing in European property and a $5 billion pool for deals in Asia.

“The size of this fund gives us the ability to commit capital in scale with speed and certainty,” Gray said in the statement.