You may remember the horror stories of employees who watched their 401(k) account balances virtually disappear when the stock price of their employer collapsed. Enron and Lehman Brothers are two of the most famous examples. To the list can now be added… RadioShack.

While employer stock in 401(k) plans is less common than it used to be, it’s still in too many of them. According to a 2013 Aon Hewitt survey, 39% of employers offer their stock as an investment option. Among those companies, 12% go even further, requiring that the employer-provided match of workers’ salary contributions be in company stock. Most employers allow employees to replace it with another investment immediately, but inertia often keeps them from doing so.

Apparently, employees don’t seem to get themselves out of the company stock even when the warning signs are already all around them – like a steadily declining share price.

A paper by the academics Ying Duan, Edith S. Hotchkiss and Yawen Jiao studied 729 troubled publicly traded companies over 20 years and found that the amounts of money that employees had in company stock remained relatively stable during periods of trouble, as did their new contributions. This is true even as the stock prices decline and the number of investors betting against the stock in the public markets through short sales increases.

You can read the entire March 21, 2015 New York Times article here.