Student Loan Xpress, a college student lender in Carmel Valley, said it is shutting down operations and laying off 124 employees.

SLX, which got its start in the early 1990s, has been hurt by tightened credit markets and a change in the regulations covering the student loan business.

The lender is a unit of New Jersey-based CIT Group Inc.

CIT spokeswoman Mary Flynn said the student lender will continue to handle existing loans at a service center in Cleveland, Ohio. It is no longer making new loans, she said.

CIT joins a growing number of private concerns that have stopped making loans and have laid off thousands of workers.

Two other lenders in the region, Virginia-based Goal Financial LLC in San Diego and College Loan Corp. in Poway, have cut staff in recent months, following their decisions to stop offering certain types of student loans.

Goal laid off 134 employees last year. College Loan laid off 260 employees, or 70 percent of its staff.

Mark Kantrowitz, the publisher of FinAid.org, a Web site that provides information on financial aid, said the biggest reason behind the retreat is the continuing turmoil in credit markets, in large part precipitated by the subprime mortgage debacle.

“Investors in the securitizations (pools of mortgage loans) who were burned by the subprime mortgages have pulled back from everything,” Kantrowitz said.

Besides roiling credit markets, lenders have seen profit margins squeezed by changes in the federal guaranteed program, he said.

More than three-quarters of the lenders making consolidation loans and about 14 percent of lenders making loans guaranteed by the federal government have exited the market, Kantrowitz said.

About 3,500 workers have lost jobs as a result, he said.

SLX may also have been impacted by an investigation into possible kickbacks to college administrators who put the companies on a “preferred lender” list.