Speculative appetites turned voracious Monday with stunning gains in a handful of security-related issues, led by one-time dot-com darling IPIX ( IPIX). Over the past month, shares of the company formerly known as Internet Pictures have skyrocketed 900% to just under $24 a share, boosting the company's market capitalization from under $25 million to roughly $220 million. In Monday trading alone, shares of San Roman, Calif.-based IPIX were rising $8.49, or 55%, to $23.99. The stock was the most actively traded on the Nasdaq Stock Market with more than 50 million shares changing hands. To put that frenzied action in perspective, consider that back on March 12 shares of IPIX were trading at $2.36 on a daily average volume of fewer than 100,000 shares. The company, which markets a sophisticated video surveillance system, is the latest darling of daytraders and speculators bidding up shares of low-float stocks, especially ones in the security sector. IPIX joins a list of other small security outfits like ICTS International ( ICTS) and Mace Security ( MACE), which were up 71% and 136%, respectively, Monday; and other recent highfliers like Arotech ( ARTX) and Magal Security ( MAGS). The group is soaring in the wake of renewed terrorism jitters, as investors fear the increasing carnage in Iraq could lead to new terror attacks in the U.S. and Europe. It's also a case of investors hoping to catch lightning in a bottle and find the next Taser International ( TASR), the stun-gun maker whose stock is up 2,300% on a split-adjusted basis since last summer. Monday's is just the latest of several speculative waves to sweep the small-cap universe this year. Other low-float darlings that already rallied this year are medical tech company Vaso Active Pharmaceuticals, garbage hauler Industrial Services of America ( IDSA), oil drilling manufacturer Unifab ( UFAB) and Internet search engine Mamma.com ( MAMA). The only thing many of these companies have in common is their low floats -- in most cases just a few million shares outstanding. With so few shares outstanding, it doesn't take much to push them higher.