In another indication of trouble in the subprime mortgage market, Countrywide Financial Corp. said Thursday that payments were late on almost 20 percent of the subprime loans the mortgage giant manages for other lenders.

The Calabasas-based lender said that delinquencies of 30 days or more on subprimes grew to 19 percent at the end of 2006. Countrywide, the nation’s largest mortgage lender, services more than $1 trillion in loans.

A surge in bad mortgages has forced more than 20 lenders to close or seek buyers in the past year, the company said in a filing.

Delinquent loans stood at 17 percent at the end of September, Countrywide said.

Shares in Countrywide closed down 90 cents, or 2.3 percent, to $37.44 Thursday on the New York Stock Exchange but gained 20 cents in aftermarket trading.