So did hedge-fund manager Eddie Lampert, whose ESL Investments bought $27.6 million of AutoZone (AZO) as the stock hit a two-year low. Lampert, who controls 38% of the company, has been buying since April.

Retailers also attracted insiders, notwithstanding fears that the coming holiday season may be the worst in years for the industry. In early October, in one of the market's worst weeks on record, the CEO of discount shoe seller DSW (DSW), Jay L. Schottenstein, shoveled more than $15 million into his company's stock, paying an average of less than $12 a share; the stock now trades for $11.50. Schottenstein's confidence says something, given his retail background. He's the former CEO of American Eagle Outfitters (AEO), and sits on the boards of American Eagle and Retail Ventures (RVI), parent of Filene's Basement.

Another apparent retail fan is Slim, who invested in industrial and financial businesses during Mexico's 1980s debt crisis. In early October, a Slim-controlled trust bought nearly $11 million of Saks (SKS) stock, boosting his already significant stake in the parent of tony Saks Fifth Avenue. Saks has fallen more than 70% in the past year, to around $5 a share. Slim paid about $7 a share.

Gates continued to boost his stake in Republic Services (RSG), the waste hauler. From Aug. 5 to Sept. 29, he invested $256.7 million in Republic, at an average price near $33. Today, the stock is around $22. Waste Management (WMI) recently dropped its bid for Republic.

At AAR (AIR), a Chicago-area aviation and aircraft-leasing concern, the CEO and five directors picked up more than $461,000 of stock at an average of $11.86 a share, just below today's price.

Financials aren't without fans, either. Five insiders bought shares of MetLife (MET) recently, reversing a multi-year trend of planned sales.

At credit-card issuer Discover Financial Services (DFS), the CEO, CFO and chief operating officer bought shares in early October at an average of $11.55 a share; the stock now trades around $10.