A combination of Yahoo Inc. and Checkfree Holdings Inc., which Yahoo is rumored to be pursuing, would threaten financial institutions, some observers said.
Yahoo is said to have designs on becoming a banking and financial services hub to strengthen its hand as the largest of the Internet portals.
"Banks are in deep trouble if this were to happen," said Avivah Litan, research director at GartnerGroup in Stamford, Conn. "If you own Checkfree, you're not going to want to share (electronic billing) content, especially with the banks."
Officials at Checkfree in Norcross, Ga., and Yahoo in Santa Clara, Calif., declined to comment on the rumors.
An executive at a bank software company said such a deal "would be good, because it would make the banks angry," spurring them to become more aggressive in developing alternatives to Checkfree for bill presentment and payment.