(Bloomberg News) Blackstone Group LP, the world's largest private-equity firm, is close to signing a deal with the California Public Employees' Retirement System for a separately managed account, according to a person with knowledge of the plans.

Blackstone and the pension, known as Calpers, are in the final stages of negotiating the deal and may announce an agreement as early as next week, said the person, who declined to be identified because the discussions are private.

Peter Rose, a spokesman for New York-based Blackstone, declined to comment. Brad Pacheco, a spokesman for Calpers, said he couldn't immediately comment.

Separately managed accounts offer cheaper fees and more control for investors, who in turn agree to commit large sums for a decade or more. Firms have been using these custom arrangements to attract investors as they compete for a shrinking pool of investor dollars. In November, the Teacher Retirement System of Texas committed $3 billion each to KKR & Co. and Apollo Global Management LLC.

Blackstone a month later won as much as $1.5 billion from the New Jersey State Investment Council, to be placed into four custom funds. The deal will save the state about $120 million in fees over the life of the agreement, the council said at the time.

Blackstone's discussions with Calpers were reported earlier today by Fortune magazine.