By David Russell, reporter at OptionMonsterNEW YORK -- Virgin Media ( VMED) has been going straight up, but on Thursday the bears stepped in. OptionMonster's tracking programs detected the purchase of more than 6,300 January 30 puts, most of which priced for 75 cents. Volume was more than 18 times open interest at the strike. Those puts lock in the price where investors can sell shares of the British cable company, so they will increase in value in the event of a drop. If it remains above $30 through expiration, however, the options will become worthless. Virgin Media's shares fell 0.73% to $32.70 Thursday, two sessions after hitting an all-time high above $34. Some investors had accurately predicted that strong move, and rang up gains of more than 50% in less than a week. The company has been in a steady uptrend since the spring and just reported strong third-quarter subscriber gains. Thursday's bearish activity seems to be more a reflection of nervousness toward the broader market, where a pullback could drag down big gainers such as Virgin Media. Overall option volume in the name was seven times greater than average Thursday, with puts accounting for more than three-quarters of the total. Russell has no positions in VMED.