Mortgage insurance turmoil strains housing market 

Mortgage insurers have been forced to adopt stricter underwriting standards, adding yet another layer of uncertainty to the housing market. A lack of mortgage insurance means some borrowers who struggle to put together a down payment could have a tougher time buying a home. Claims on policies that mortgage insurers sold during the boom have hit hard. MGIC Investment Corp., the largest mortgage insurer in the country by market share, reported that it posted a $1.47 billion loss in the fourth quarter. Now, MGIC won’t insure borrowers who won’t put down at least 5 percent in several major metropolitan areas and in four states: Arizona, Florida, California and Nevada. The change has already taken effect in Florida and California