According to American Bankruptcy Institute data, more than 323,000 businesses filed for bankruptcy from 2004 through 2010, more than 39,000 of them in California. This state's share of all U.S. business bankruptcies has increased from 12.4% in 2007 to 15.7% in 2010, an indication that the recession hit California businesses harder than their counterparts nationwide.
http://www.ocregister.com/articles/bankruptcy-299278-businesses-small.html
Our office files Ch 7 for business, or sole proprietors in Ch 13.