Lehman Bros. Holdings Inc., the fourth-largest U.S. securities firm, rose 15 percent in New York trading this morning after a report that Korea Development Bank is “open to” an acquisition, Bloomberg reported.

Lehman’s stock price climbed $2.03 to reach $15.75 before the official opening of New York Stock Exchange trading. Shares of the New York-based company had dropped almost 80 percent this year before today, making it the worst performer on the 11-company Amex Securities Broker/Dealer Index.

“We are studying a number of options and are open to all possibilities, which could include (buying) Lehman,” a Korea Development Bank spokesman said, according to a Reuters report.

Lehman, the largest underwriter of mortgage bonds before the subprime market collapsed, lost the confidence of investors in the past year as it struggled to pare debt holdings. The bank has reported write-downs and credit losses of $8.2 billion in the past 12 months, according to data compiled by Bloomberg.

Lehman spokesman Mark Lane declined to comment on the Reuters report. Korea Development Bank CEO Min Euoo Sung also declined to comment.

“The Koreans are signaling a desire to buy Lehman,” Ladenburg Thalmann & Co. analyst Richard Bove said today in an interview. “Lehman is massively undervalued, and this is a cheap stock.”

Bove said yesterday that Lehman was a candidate for a hostile takeover because the company, led by CEO Richard Fuld, is unwilling to sell at a depressed price.

The Financial Times reported yesterday that Lehman failed to sell a 50 percent stake to Korea Development Bank and China’s Citic Securities Co. The buyers walked away after deciding Lehman was demanding too high a price, Financial Times said, citing people familiar with the Asian lenders.