Arch Capital Group Ltd., the insurer that struck a deal to buy assets from mortgage guarantor PMI Mortgage Insurance Co., said it has won approval from Fannie Mae and Freddie Mac, the seller’s largest creditors.

After discussion with the creditors, the deal was revised so that the initial payment for an insurance unit will be 80 percent of book value, rather than 60 percent, Bermuda-based Arch said today in a regulatory filing.