http://www.usinvestorclubs.org/article.php?id=6
For many years now U.S corporations have been legally carrying two sets of financial books. One set of books was given to the IRS when it came to tax time. Many of these reports showed well known, leading corporations reporting a loss for the year which reduced their taxable income, or in some cases allowed them to avoid paying taxes at all. In these accounting records the companies that issued stock options to their employees deducted the value of these options as an expense. After all, they did have value, and the company did give them to their employees for services rendered. These options were often given as compensation and incentives, in lieu of higher wages and salaries. It definitely saved the companies a lot of cash flow, an important commodity for any business.
But then we have that second set of books. The second set of books was presented to the SEC and the public at quarterly earnings reporting time. These books did not deduct the value of the options granted to employees, and the granted option values only showed up as teeny-tiny footnotes at the bottom of the pages, and at the back of the quarterly and annual reports. By doing this companies were able to report that they had made money, and had met those important earnings projections. The reasoning was that if a company had to show these options grants as an expense, as it did with the filings with the IRS, we would see a huge number of companies that never made a profit. And if that were the case they would not the ability to leverage themselves, with stock and options, into giant corporations such as WorldCom. Nor could they get employees to work for lower wages by offering stock options.
Two sets of books -- one for the IRS, one for the SEC.
I would guess this is the reason, but don't know for sure.
I also would not doubt CTJ's (Citizens for Tax Justice). I have found they do good work.