Sterling Bancshares Inc (SBIB.O) posted a surprise quarterly loss, hurt by a three-fold increase in provision for loan losses and higher charge-offs.

For the third quarter, Sterling Bancshares, the holding company of Sterling Bank, said net loss was $6.1 million, or 7 cents a share, compared with a net income of $7.1 million, or 10 cents a share, a year earlier.

Provision for loan losses jumped to $27.5 million, while net interest income fell 3 percent to $47.9 million.

The company said it charged-off $15.9 million of nonperforming loans, which were considered collateral dependent, and $9.6 million related to Semgroup, an energy customer that is currently in Chapter 11 bankruptcy.

Shares of the company closed at $6.52 Wednesday on Nasdaq.