NEW YORK (AP) — Bermuda insurance company holding group Enstar Group Ltd. said yesterday it agreed to commit $200 million to the proposed acquisition of SLM Corp., commonly known as Sallie Mae, by private-equity firm J.C. Flowers & Co. and three other investors.Sallie Mae said on Monday it agreed to the $25 billion going-private transaction.

Under the terms of Enstar’s agreement with J.C. Flowers, Enstar will commit $200 million to one or more co-investment vehicles that will be created to acquire Sallie Mae. Previously, the company said it had committed to invest up to $100 million.

Enstar plans to reduce its investment if J.C. Flowers is able to obtain commitments from other investors.

J.C. Flowers is controlled by J. Christopher Flowers, an Enstar director and one its largest shareholders. John J. Oros, executive chairman of Enstar, is a managing director of J.C. Flowers.

Under the terms of the acquisition agreement, J.C. Flowers and private-equity firm Friedman Fleischer & Lowe will own 50.2 percent of the company. Bank of America and JPMorgan Chase each will own 24.9 percent. Sallie Mae’s board unanimously approved the deal, which was signed on Sunday evening.

The acquisition is expected to close in late 2007, pending the approval of Sallie Mae’s stockholders and regulatory approvals.

Enstar shares dipped 5 cents yesterday to close at $100.95 on the Nasdaq Stock Market.