By John S. McClenahen During the past three months, there's been some tightening of standards and terms for bank loans to commercial and industrial customers -- especially small firms. The net percentage of U.S. banks imposing tighter standards on commercial and industrial loans to large and mid-sized firms edged down to 20% from 22% between August and October, reveal data from the Federal Reserve System. In contrast, the net percentage of banks tightening loan standards for small firms soared to nearly 20% in October from just 6% in August. Loan terms showed a similar pattern. For example, the percentage of banks raising premiums on riskier loans to large and mid-sized firms declined to 40% from 50% between August and October. But the fraction of banks raising premiums on riskier loans to small firms increased from more than one-fifth to more than one-third between August and October.