Proforma results aren&#x27;t necessarily bad, they are the company trying to show themselves in the best possible light.  Historically they were used to show how the company was doing ex of one time events( almost exclusively negative events) such as layoffs, lawsuit settlements, divesting&#x2F;closing money loosing units, etc.<p>The biggest issue I see is that often the company will clearly spend more time with their proforma results than their GAAP results.<p>The outcome from this is that often when analyst or data companies try to put together metrics on a company they&#x27;ll use GAAP results but if a ratio they want isn&#x27;t present they&#x27;ll substitute the ratio from the proforma results.<p>This means many of the data you get on google finance or even Bloomberg is an amalgamation of the two, which leads to garbage in-garbage out.<p>Side note: if you can clean data, you&#x27;ll have a job for life!!!<p>Tech companies tend to be big users of pro forma results.  Facebook famously turned a $700 million loss (GAAP) in 2012 into a $400 profit (Pro forma) by not using Black Scholes to calculate the cost of employee stock options.<p>Groupon was another poster child for pushing pro forma results vs GAAP results and that turned out about as well as you&#x27;d expect.  Just google &quot;Groupon pro forma vs GAAP&quot;.