I can think of several reasons why America s executives wouldn t buy their companies shares right now despite low prices.

They might be strapped. Stephen Schwarzman, chairman of private equity giant Blackstone Group (BX), speaking at the World Economic Forum in Davos, Switzerland, last month, issued a startling estimate of the global recession s toll to date. The world has lost 40% of its wealth in a year and a quarter, he reckons.

They might be barred. Companies typically disallow executive trading around earnings reports. Some 80% of big companies have reported in the past month.

They also might be prudent. Investors applaud executives who load up on their companies shares, since bosses have a better view of day-to-day operations than the rest of us, and since stock purchases bespeak confidence. But it s risky for any investor, executives included, to bet too much of their savings on the same company responsible for their income.

That said, plenty of bosses are still buying. Newsletter InsiderInsights counts 372 companies with insider buys last week versus 357 with sells. Some of these purchases seem like daredevil moves: big purchases of plummeting shares with few apparent signs of a turnaround to come. Maybe they're on to something, or maybe they're about to lose a bundle.

Bank of America (BAC) chairman and chief executive Ken Lewis has spent more than $2 million on shares this year at prices ranging from $4.78 to $6.06. (Shares go for around $5 now.) JPMorgan Chase (JPM) head James Dimon spent more than $11 million in mid-January buying at $22 and change, about where the stock is currently trading. American Express (AXP), Goldman Sachs (GS) and U.S. Bancorp (USB) saw big purchases, too. This, despite these companies fortunes in coming quarters depending upon consumers ability to repay what they owe, which in turn will depend on employment and the economy -- things for which bank executives have no special foreknowledge.

Motorola (MOT) has two chief executives. Both bought stock earlier this month for a combined 725,000 shares. That cost less than $3 million; at the stock s peak in March 2000, it would have cost more than $40 million. Investors will have to look hard to find reasons to love Motorola right now. The company s mobile phones are quickly losing fans. Last quarter it captured 6.5% of global market share, down from 8.4% in the third quarter and 12.4% a year ago. The company has more than $2 billion in spare cash, enough to finance a turnaround effort. But the handset business is worrisomely competitive, and stockholders won t be paid to wait and see. Days before the bosses bought, Motorola suspended its dividend.

A plunge in computer demand has crushed hard drive makers. Seagate (STX) shares have lost 80% in a year. On Jan. 21 the company said its second-quarter sales dropped 34% as it sold fewer drives and settled for reduced prices amid an industry-wide glut. That resulted in a loss of $496 million versus a $403 million profit a year earlier. The stock now trades near book value after questionable assets have been written off. A week after reporting its second-quarter loss, Seagate said it would tack on a $2.3 billion charge for goodwill (read: the amount by which it overpaid for Maxtor in 2006). Stephen Luczo, who ran the company from 1998 to 2004 and returned in January, bought 500,000 shares at month s end at $3.56 and another 500,000 last week at $4.45. The company has plans to cut 10% of its U.S. workforce and has reduced but not eliminated its dividend. Current yield: 2.7%.

Furniture Brands (FBN) shares have dropped from $42 to less than $2 in just under seven years as the easy house-equity gains that once financed living room sets have vanished. In its most recent quarter the company posted a staggering loss of $7 a share as it wrote down intangible assets and tax credits that had become worthless and took a charge for restructuring. The company is left with $5 a share in book value, less than $100 million in net debt and inventories that seem a better fit with current demand. Earlier this month, the chief executive and general counsel together bought 60,000 shares at just over $2.