LOS ANGELES — Bank of America Corp., under pressure to raise capital and cut risks, is severing lines of credit to some small-business owners who have used them to stay afloat.

The Charlotte, N.C., bank is demanding that these customers pay off their credit line balances all at once instead of making monthly payments. If they can’t pay in full, they are being offered new repayment plans for as long as five years, but with far higher interest rates than their original credit lines had.

Business owners complain that BofA’s credit squeeze is abrupt and could strain their small companies and even put them out of business. The credit cutoff is coming at a time when the California economy can’t seem to catch a break, and bucks what the financial industry says is a new trend of easing standards on business loans.

One such customer, Babak Zahabizadeh, was told in a letter that the $96,000 debt carried by his Burbank messenger service must be repaid Jan. 25. A loan officer offered multiple alternatives over the phone that Zahabizadeh called unaffordable, including paying off the debt at 12 percent interest over two years. That’s about $4,500 a month, nearly 10 times his current interest-only payment.

“I was like, ‘Dude, you’re calling a guy who’s barely surviving!’” he said. “My final word was that I can double my payment — but not triple or quadruple it. I told them if they apply too much pressure they’re going to push me into bankruptcy.”

The capped credit lines stem from a corporate overhaul launched by Brian Moynihan, who became Bank of America’s chief executive in 2010. He promised to address losses caused by loose lending and rapid expansion by reining in risks and shedding investments deemed non-core.

BofA spokesman Jefferson George said a “very small percentage” of small-business customers have been affected by the changes. He would not provide exact numbers except to say it wasn’t in the hundreds of thousands.