Sharp Corp.'s biggest one-day stock slide in 37 years sent its shares sold short in Japanese margin-trading accounts surging to a daily record as investors bet volatility will continue.

Sharp, maker of Aquos televisions and phones, plummeted 28 percent, the most since at least September 1974, on Friday after the company widened its loss forecast. The number of shares held in margin-trading accounts that profit if the stock falls jumped 10 times on Aug. 3 to 24.65 million, the highest since Japan Securities Finance Co. began reporting daily data in August 1997. Holdings in accounts that profit if shares go up rose the same day to 6.69 million, the highest since 2004, according to JSF data compiled by Bloomberg.

Monday, Sharp shares dropped 5.7 percent to ¥181.