Shares of large companies tend to trade more frequently than those of small ones, all else held equal. Among the behemoths that make up the S&P 500 index, the median company has experienced an average daily trading volume in recent days equal to 1.1% of its outstanding shares. For S&P SmallCap 600 members, the median is 0.7%.

The small companies below, all members of the 600 index, have defied this tendency. For each firm, 3% to 5% of its outstanding shares have changed hands each day of late. However, don't rush to conclusions about dramatic developments being announced soon. A quick glance at trading patterns for these shares suggests they've simply become favorite vehicles of day traders. Their prices tend to swing wildly with all that trading volume, which is useful to speculators but not of much comfort to long-term investors.

Crocs
Trading volume as percentage of shares outstanding: 4%

Crocs sells rubbery clogs, chiefly. The shoes proved a hit several years ago among workers who spend plenty of time on their feet around slippery surfaces, like doctors and nurses, and they quickly became a full-blown fad. Sales grew from just over $1 million to $847 million over the four years ended 2007. Then they fell into steep decline; last year, sales totaled $645 million. Cheap knockoffs cut into sales of Crocs clogs, and the company struggled to find other designs for its patented material and low-labor injection molding process. Thus, Crocs has remained highly dependent on summer sales.

New management seems to be getting results. The company recently reported sales growth in all regions, including impressive growth in Europe and Asia, resulting in a return to profitability. A recently launched line of back-to-school shoes might boost autumn sales. Wall Street estimates that Crocs will retake the $800 million sales mark next year. Shares, which topped $60 in 2007 and plunged to $1 and change the following year, now sell for close to $12. Two of four analysts who cover the stock have changed their opinion of it since April, issuing recommendations to buy.

Kulicke & Soffa Industries
Trading volume as percentage of shares outstanding: 5%

Kulicke & Soffa Industries manufactures semiconductor assembly equipment, along with much excitement for stock traders. Owed to the boom-and-bust nature of the chip business, and perhaps to the company's limited supply of shares available for trading, the stock has multiplied in value several-fold, only to tumble again, during at least six periods since 1990. For all of the ups and downs, 20-year holders of the stock (if there are any) have gotten a compounded annual return of just under 5% -- a couple of percentage points less than a pair of 10-year Treasury bonds provided over that span.

Still, the stock remains a fertile source of short-term trading drama. It has jumped fivefold in value since March 2009, and a sudden resurgence of demand for electronics recently returned the company to solid profitability. Shares sell for only four times forecast earnings for the company's fiscal year ending Oct. 3, perhaps because investors aren't quite convinced the current pace of demand is sustainable.

The Great Atlantic and Pacific Tea Company
Trading volume as percentage of shares outstanding: 3%

Originally a mail-order tea business operating out of Lower Manhattan, The Great Atlantic and Pacific Tea Company has operated its A&P supermarkets for nearly a century. Price competition has turned brutal in recent years, with mass merchants like Wal-Mart and Target (TGT) adding groceries to their stores. Great Atlantic last turned a profit in fiscal 2006. The following year it paid $1.3 billion for rival Pathmark.

Today, the company has a stock market value of about $145 million -- some $30 million less than its last reported cash stockpile. Perhaps that is fueling frantic stock speculation, with a massive contingent of short-sellers betting on the company's demise, and buyers betting on a takeover or turnaround. Signs of the latter are few, so far. Sales at longstanding stores are eroding, along with market share. However, the company recently named a new chief executive, who outlined a plan to make stores cleaner and more customer friendly, to improve variety and to reduce prices on strategic items. Perky daytime television host Kelly Ripa is signed on as spokeswoman for a new ad campaign.