A certain group of companies might want to recognize a looming change in their income statements: the tax benefits of stock options are about to start appearing there.

The change will come about thanks to new rules for stock option expensing adopted earlier this year, that will take effect in December. Essentially, it works like this: a company grants stock options to employees in one year, and those options grow in value (theoretically) over time as the stock price rises. As the option becomes more valuable, however, the tax benefits that grow along with it get harder for the company to report.

The Financial Accounting Standards Board adopted a change to simplify that treatment of tax benefits. Currently, companies recognize the benefits as Additional Paid-In Capital, listed on the balance sheet. As of Dec. 15, however, companies will be required to recognize all tax benefits (or deficiencies, if your shares have tanked) on the income statement.

This all means that if you dole out lots of stock options and your stock is rising, your income statement will see a nice boost as the growing tax benefits start appearing there next year. Then again, if your stock tanks, the income statement will look that much worse; financial reporting will be simplified, but the numbers themselves will be more volatile.

OK then—if that’s the change that’s coming, whose income statement will feel it the most? That’s easy enough for Calcbench users to find.

We looked at the S&P 500 (plus Twitter because, well, Twitter). What were each company’s revenues for 2015, and what were its equity compensation costs not yet recognized? And then, what was the ratio of those two numbers? The larger the ratio, the more potential stock option benefit you have.

A few keystrokes later, we found that this change will matter only to a small portion of the S&P 500. The ratio is less than 1 percent for 305 of the S&P 500, and less than 5 percent for 464 of them. Only 14 companies have a ratio larger than 10 percent, and they are the following.

No surprise here, really; the list is larded with technology and pharmaceutical companies, which are exactly the firms that dole out lots of options while they race to rack up revenue.

The pro-cyclicality of this rule change might tempt companies to publish more non-GAAP net income metrics, that exclude options costs. Plenty of tech companies already do that (Facebook, Twitter, and Google among them), and if we start to see more income volatility thanks to this change, they’ll have all the more incentive to embrace non-GAAP even more.