Martin O'Malley

In her own speech on the issue last week, Clinton proposed a sliding scale capital gains tax rate that would encourage investors to hold equities for longer, rather than turning them over for quick profit.

Companies have been allowed to repurchase their shares on the open market with virtually no regulatory limits since 1982, when the SEC instituted Rule 10b-18 of the Securities Exchange Act. Under the rule, a corporation’s board of directors can authorize senior executives to repurchase up to a certain dollar amount of stock over a specified or open-ended period of time, and the company must publicly announce the buyback program. After that, management can buy a large number of the company’s shares on any given business day without fear that the SEC will charge it with stock-price manipulation—provided, among other things, that the amount does not exceed a “safe harbor” of 25% of the previous four weeks’ average daily trading volume. The SEC requires companies to report total quarterly repurchases but not daily ones, meaning that it cannot determine whether a company has breached the 25% limit without a special investigation.

Despite the escalation in buybacks over the past three decades, the SEC has only rarely launched proceedings against a company for using them to manipulate its stock price. And even within the 25% limit, companies can still make huge purchases: Exxon Mobil, by far the biggest stock repurchaser from 2003 to 2012, can buy back about $300 million worth of shares a day, and Apple up to $1.5 billion a day. In essence, Rule 10b-18 legalized stock market manipulation through open-market repurchases.

The rule was a major departure from the agency’s original mandate, laid out in the Securities Exchange Act in 1934. The act was a reaction to a host of unscrupulous activities that had fueled speculation in the Roaring ’20s, leading to the stock market crash of 1929 and the Great Depression. To prevent such shenanigans, the act gave the SEC broad powers to issue rules and regulations.

During the Reagan years, the SEC began to roll back those rules. The commission’s chairman from 1981 to 1987 was John Shad, a former vice chairman of E.F. Hutton and the first Wall Street insider to lead the commission in 50 years. He believed that the deregulation of securities markets would channel savings into economic investments more efficiently and that the isolated cases of fraud and manipulation that might go undetected did not justify onerous disclosure requirements for companies. The SEC’s adoption of Rule 10b-18 reflected that point of view.