NewStar Financial Inc. is the business lender backed by PE firms including Corsair Capital LLC and Capital Z Partners Management LLC. According to sources with direct knowledge regarding the matter, NewStar had been exploring a sale.

According to one of the sources, NewStar had been working with Credit Suisse Group to solicit offers for the possible sale. The sources spoke in condition of anonymity as the matter was held confidential in nature. The share of Boston based NewStar increased 13% to USD17.76 today. This was its highest from February 2007 which gave the company a market value of around USD863 million.

NewStar is a specialty lender offering loans to manufacturing, energy and health-care firms which are at higher interest rates. Last July, CapitalSource Inc. which also lends to businesses, agreed on sale to PacWest Bancorp in a USD2.3 billion transaction.

NewStar spokesman Robert Brown refused to give comments regarding the report. Credit Suisse spokesperson also did not give any statement.