A minuscule garbage company is suddenly one of the hottest stocks of the year. Shares of Industrial Services of America ( IDSA), a small Kentucky-based waste management firm, are up a cool 923% this year, rising almost 25% in early Monday trading. More than 4 million shares traded in Monday's first 90 minutes, making it one of the most actively traded stocks on the Nasdaq. The frenzied early activity pushed the stock up $8.13, or 23%, to $43.40. It's remarkable volume for a stock with just 1.6 million shares outstanding. Industrial Services' surge follows only one piece of recent news: an announcement late last week of a 2-for-1 stock split. Trading in the stock has exploded in the past two weeks -- especially after the split announcement -- with the stock rising 450% in that period alone. The surge in Industrial Services, a company that earned $668,000 last year, or 41 cents a share, defies easy explanation. Company officials could not be reached for comment on the trading. One hedge manager, who doesn't own shares of the stock, said the trading was unusual and seemed out of the ordinary. A Nasdaq official declined to comment on the trading. In the past, investors have been known to buy shares of stock after hearing about a split, which technically should have no economic bearing on the shares. Postsplit appreciation is a trading pattern that occurred frequently during the stock market bubble and is one that continues to mystify market watchers. Of course, a stock split doesn't change the value of a stock. An investor who owns one share of a $10 stock, simply has two $5 shares following a 2-for-1 stock split. Some investors no doubt buy a stock that has announced a split on the theory that many retail investors don't understand the concept and they will be able to trade it as short-term momentum play.