As companies’ executive pay packages have swelled from stock-based compensation, some of those same companies have been buying back more shares.

But what if the CEO of a company is simultaneously selling a lot of shares?

Buybacks can be a good thing for investors if they are large enough to lower share counts and raise earnings per share. A decision by a chief executive officer to sell stock holdings may not mean he or she is losing faith in the stock. Still, it may make investors think twice, especially if the company is buying back shares at record prices, as so many companies have been doing during the bull market.

“Some CEOs are saying that their shares are cheap and a good value for shareholders to buy [via their companies’ buybacks], while they are personally doing something meaningfully different with their personal stakes” in the companies, Management CV CEO Renny Ponvert said in an interview July 25.

As a follow-up to the data set featured in last week’s look at “30 companies that might cut dividend payments to investors,” Management CV has provided a list of 10 companies that have spent at least $1 billion on share repurchases over the past year, while the CEO has been a net seller of more than $10 million in shares over the past 18 months:

About the data:

• The CEOs’ stock sales include the exercising of vested stock-option grants. Rather than include the entire proceeds in the net sales column, Management CV included only the difference between the strike price and the actual sales price, so as not to exaggerate the figures.

• These are actual buybacks, not simply buyback programs that have been announced.

• The payout ratio includes dividends and share buybacks divided by earnings before interest and taxes (EBIT) over the past eight reported quarters.

• The Management CV CEO ranking, from 1 (best) to 5 (worst), is “a time-weighted, 10-year work history/track record, to score that person across time, jobs and companies” that he or she has worked for, according to Ponvert. The financial factors that make up the rating include payout ratios, debt to equity, debt to EBIT and growth rates for EBIT against industry peer groups.

• There’s no figure for debt as a percentage of equity for AutoZone Inc. AZO, -1.62% because the company reported having a stockholders’ deficit (negative equity) of $1.7 billion as of May 6. For Boeing Co. BA, +0.28% , this figure is very high, because the company had $10.799 billion in debt and $95 million in total shareholders’ equity as of March 31.

• One obvious reason a CEO would want to sell a lot of shares is to diversify his or her holdings as part of an estate-planning process. This is why Management CV limited the list to CEOs who have not announced any plans to retire over the next 18 months.

Another point Ponvert made is that a CEO might say a stake in his or her company hasn’t changed, because new stock-option grants make up for the grants they have exercised or shares they have sold. But if the CEO has been selling options that are “deeper in the money” than the new ones, they have actually reduced the risk of their stake in the company “dramatically.”

Being included on the list doesn’t necessarily mean a CEO is doing something wrong by selling shares or exercising stock options. But it can be useful to shareholders who may be weighing a decision on whether to keep holding the shares — or bail.