Mortgage credit availability increased in January amidst wider access to jumbo loans, according to the Mortgage Bankers Association.

The Mortgage Credit Availability Index rose 1.1% to 177.1, the MBA reported Tuesday. An increase in the index indicates a loosening of lending standards, based on a benchmark level set in March 2012 at 100.

"Mortgage credit availability increased for the fifth consecutive month in January, driven by increased availability of jumbo loan programs," Lynn Fisher, MBA's vice president of research and economics, said in a news release.

"We saw a particular increase in agency jumbo programs that focus on loans in high-cost areas that exceed the baseline conforming loan limit of $424,000 but which are still eligible for purchase by the [government-sponsored enterprises]."

Fisher noted that the increase to the GSE loan limits did likely have an indirect effect on the jumbo MCAI as much of that uptick was caused by several investors rolling out new jumbo loan programs in January.

Of the four component indices, the jumbo MCAI saw the greatest increase in availability over the month, rising 4.7% month over month. This was followed by the conventional MCAI and the government MCAI, which rose by 2.3% and 0.2%, respectively. The conforming MCAI decreased 0.1% over the month.