Fitch Ratings reported 12.96% of the $564 billion fixed-rate commercial mortgage-backed securities market is in default as of March 31.

The rate increased 25 basis points from the end of last year as roughly $1.7 billion in CMBS loans went at least 60 days delinquent. Fitch excludes loans that do not refinance at maturity. If it did, the default rate would be closer to 15.5%.

Roughly $13.7 billion in CMBS loans went into default in 2011, a 38% from the year before. Analysts don't expect the pace to change.

"Fitch expects the pace of new defaults in 2012 to be relatively stable to 2011 levels," the credit ratings agency said.

In the first quarter, offices continued to lead in problem loans, taking nearly half of all defaults, followed by retail commercial mortgages, which took 29% of defaults during the period.