SHARES in Lehman Brothers fell the most in a week after options traders speculated the bank was facing funding shortages, which increased bearish bets on the stock. The company said the speculation was unfounded. Lehman declined 8.9 per cent to $US38.71 in New York. The shares have lost 41 per cent this year amid more than $US200 billion ($217 billion) of industry-wide losses in mortgage-related securities. The number of bearish put options traded on Lehman stock exceeded calls by 3-to-1 and put volume in the first three hours of the day topped the daily average of the past 20 sessions. Speculation that Wall Street firms cannot fund their operations has contributed to share price swings. Bear Stearns required an emergency bailout by the Federal Reserve two weeks ago after trading partners stopped doing business and capital dried up. "Lehman has been hurt by the same rumours as Bear," said Sveinn Palsson, a derivatives strategist at Credit Suisse in New York.