It’s generally accepted that a lot of accounting isn’t, well, generally accepted.

But with more and more companies promoting bookkeeping that deviates from U.S. standards known as GAAP, for Generally Accepted Accounting Principles, the Securities and Exchange Commission is warning about getting too creative.

The concern is too much non-GAAP accounting could make it harder for investors to size up companies -- a risk that was driven home during the Nasdaq boom of the late 1990s and more recently at Groupon Inc., which before going public used profit measures that stripped out some of its biggest costs. Groupon has mostly lost money and market value ever since.

Using non-standard accounting is perfectly legal, provided companies also report the official GAAP numbers. These days, young companies aren’t the only ones offering up two sets of books.

ConocoPhillips, which dates back to back to 1875, was admonished by the SEC last year for promoting accounting metrics that the agency said cushioned the oil driller’s books against the plunge in oil prices. ConocoPhillips based some of its calculations on prices from 2013, before crude cratered. The trick added $755 million to ConocoPhillips’ home-cooked measure of profit.

“That brings new meaning to the old phrase, ‘pick a number, any number,”’ said Lynn Turner, a former chief accountant at the SEC. “It’s exceedingly aggressive, and everyone would know that it’s aggressive.”

A ConocoPhillips spokesman said the company was trying to help investors compare results from one year to the next by focusing on factors the company can control, like taxes, royalties and output. To that end, it stripped out energy price trends, the company told the SEC in a letter in June.

But the SEC said the approach looked too opportunistic and ordered ConocoPhillips to stand down, Keith Higgins, the SEC’s director of corporate finance, said at a conference in January.

While creative accounting has been around forever, non-traditional measures -- “metrics,” in industry parlance -- have been on the rise lately. Companies routinely highlight the non-GAAP results in press releases that announce earnings, and Wall Street analysts often fixate on the adjusted figures. The number of companies in the Standard & Poor’s 500 Index reporting non-GAAP results rose to 334 in 2014 from 232 in 2009, according to research from The Analyst’s Accounting Observer.

That’s why the SEC is worried some companies might be pushing the envelope, with Chair Mary Jo White warning in December that non-GAAP figures can be misleading.