IndyMac Bancorp Inc. continued its push to bolster its shares and distance itself from the subprime loan meltdown.

It worked, at least on Wall Street Thursday.

The Pasadena-based thrift called concerns about subprime defaults spilling into Alt-A home loans “overblown,” and its share price jumped 5.1 percent to close at $32.74.

The stock has dropped by more than a quarter so far this year and was down as much as 40 percent earlier in March, but has rebounded in recent weeks.

The company, which was the largest Alt-A originator in 2006, disclosed loss and delinquency data on its loans to show that its business is withstanding the shakeout in the lower end of the mortgage market.

According to the data, the rate of losses on Alt-A loans IndyMac originated from 2002 through 2006 is less than one basis point. The overall industry’s rate was 4.7 basis points, the company said. (A basis point is one hundredth of a percentage point.)

Skeptical analysts pointed that the data is simply previously released figures repackaged and suggested that the announcement amounted to nothing more than an attempt to boost the stock. IndyMac Chief Executive Michael Perry and director Robert Hunt each bought more than $1 million worth of the struggling lender’s shares over the past week in a likely show of support for the company.

IndyMac’s announcement comes a day after California Attorney General Jerry Brown disclosed plans for an investigation into the lending practices of California mortgage companies. About 13 percent of the nation’s subprime loans are in California, making it the largest U.S. subprime market, according to the Washington-based Mortgage Bankers Association.