Shares in IndyMac Bancorp dropped nearly 6 percent Friday after Moody’s Investors Service cut the lender’s credit rating deeper into “junk” territory late Thursday.

The credit service said the downgrade was due to the Pasadena-based mortgage lender’s struggling business and the declining value of its portfolio of home loans.

Moody’s cut IndyMac’s credit rating to “B1” from “Ba2,” and said that IndyMac’s credit is “highly speculative.” It said the struggling company will continue to lose money for several quarters.

“We expect IndyMac to lose market share and struggle to be cost-competitive as an agency-only originator in 2008,” Moody’s said.

The downgrade comes as a group of investors led by Ramat Securities Ltd. announced that they have acquired a 7.4 percent stake in IndyMac.

Ramat is led by Ohio real estate operator Howard Amster. It said in a regulatory filing with the Securities and Exchange Commission that the group doesn’t intend to seek an “extraordinary corporate transaction” such as a merger.

IndyMac also announced earlier this week that it was cutting costs by cutting up to 24 percent of its entire workforce, which is about 2,400 jobs total.

Shares in IndyMac declined 5.7 percent to $4.47 in afternoon trading Friday on the New York Stock Exchange. Shares have declined nearly 90 percent over the past year.