When General Motors launched Saturn, in 1985, the small-car division was GM's response to surging demand for Japanese brands. At first, consumers were very receptive to what was billed as “a new kind of car company,” but sales peaked in 1994 and then drifted steadily downward. GM reorganized the division, taking away some of its autonomy in order to leverage the parent company's economies of scale, and in 2004 GM agreed to invest a further $3 billion to rejuvenate the brand. But 21 years and billions of dollars after its founding, it has yet to earn a profit. Similarly, Polaroid, the pioneer of instant photography and the employer of more than 10,000 people in the 1980s, failed to find a niche in the digital market. A series of layoffs and restructurings culminated in bankruptcy, in October 2001.

These stories illustrate a common business problem: staying too long with a losing venture. Faced with the prospect of exiting a project, a business, or an industry, executives tend to hang on despite clear signs that it's time to bail out. Indeed, when companies do finally exit, the spur is often the arrival of a new senior executive or a crisis, such as a seriously downgraded credit rating.

Research bears out the tendency of companies to linger. One study showed that as a business ages, the average total return to shareholders tends to decline. For most of the divestitures in the sample, the seller would have received a higher price had it sold earlier. Finally, researchers who studied the entry and exit patterns of businesses across industries found that companies are more likely to exit at the troughs of business cycles—usually the worst time to sell.

Why is it so difficult to divest a business at the right time or to exit a failing project and redirect corporate resources? Many factors play a role, from the fact that managers who shepherd an exit often must eliminate their own jobs to the costs that companies incur for layoffs, worker buyouts, and accelerated depreciation. Yet a primary reason is the psychological biases that affect human decision making and lead executives astray when they confront an unsuccessful enterprise or initiative. Such biases routinely cause companies to ignore danger signs, to refrain from adjusting goals in the face of new information, and to throw good money after bad.

In contrast to other important corporate decisions, such as whether to make acquisitions or enter new markets, bad timing in exit decisions tends to go in one direction, since companies rarely exit or divest too early. An awareness of this fact should make it easier to avoid errors—and does, if companies identify the biases at play, determine where in the decision-making process they crop up, and then adopt mechanisms to minimize their impact. Techniques such as contingent road maps and tools borrowed from private equity firms can help companies to decide objectively whether they should halt a failing project or business and to navigate the complexities of the exit.