Aiful Corp. said it may sue Lehman Brothers Holdings Inc. for saying Japan's biggest consumer finance company by assets may be insolvent, triggering a 25 percent slide in its share price.

Aiful has "no problems with funding," the lender said in a statement Friday to the Tokyo Stock Exchange. "We will continue to protest against Lehman Brothers, and to recover our honor and trust, we are considering taking legal action."

Lehman analyst Walter Altherr said in a June 23 report that Aiful's parent company is "arguably insolvent."