The shares of Boston Scientific (BSX: sentiment, chart, options) have been hammered lately, with the stock down 26% for the week -- roughly doubling the steep losses swallowed by the broad-market indices. As it turns out, the price plunge is at least partially attributable to forced selling by co-founder and chairman Peter Nicholas. In an SEC filing late Thursday, he reported selling 100,000 shares on Tuesday at an average price of $7.15 in order to meet a margin call.

In fact, Nicholas has sold more than 25 million BSX shares since October 8 to meet margin requirements. The increased selling pressure on Boston Scientific forced the stock yesterday to an intraday nadir of $5.41, its lowest price since March 1995.

BSX is bouncing back today, though, with the equity up 4.6% in the first hour of trading. Option speculators have reacted to the stock's recent slide by loading up on put options. During the past 10 days, investors on the International Securities Exchange (ISE) have bought to open 2.3 puts for every call. This ratio ranks higher than 79% of other such readings in the past year, revealing an unusually high level of put activity on the medical-device maker.