The number of chief executive officers fired for ethical lapses more than doubled in the U.S. and Canada in the past five years—a sign, researchers say, that corporate directors are increasingly unwilling to tolerate misbehavior.

Fourteen North American CEOs were ousted for ethical lapses from 2012 to 2016, compared with six in the preceding five-year period, according to a study of 2,500 global companies by PwC. The researchers included executives who left because of their own improper conduct or that of employees, so if, for example, a CEO was forced out because of widespread fraud in the organization, that counted as well.

are expensive, triggering costly severance payments and share price declines. Stock value typically drops by 13.5 percent relative to a company’s regional index during the two-year period around a CEO’s ouster, according to PwC, and executives often collect tens of millions on their way out the door.

Beyond the immediate financial costs, the firing of a CEO for improper conduct hurts a company’s reputation for five years after the incident has passed, according to a 2016 Stanford University analysis that studied 38 examples of bosses behaving badly from 2000 to 2015. A separate Stanford study found that more than half of the general public supports the firing of misbehaving bosses.

Gary Neilson, one of the PwC study’s authors, said a handful of factors have converged to make it less likely a board will look the other way when there are ethical lapses. Activist shareholders are more insistent, and corporate directors have new liabilities for corporate malfeasance. Technology has made it easier to track and prove misdeeds, and any public outrage is amplified by social media. In emerging markets, a bribery crackdown led to a 141 percent increase in CEO dismissals.

To mitigate costs, and perhaps, the perceived injustice of a cheating or lying CEO receiving millions in severance, more boards are demanding the ability to reclaim compensation if an executive has engaged in wrongdoing that causes a financial restatement. Wells Fargo’s board recovered $180 million in awards from employees, including ex-CEO John Stumpf and former community banking chief Carrie Tolstedt, as a result of a scandal involving legions of bogus accounts opened without customer permission.

“We’re going through a re-setting period,” Neilson of PwC said. “Over time, as companies get much better at this, the numbers should go down. A lot of this is about discovery.”