An SEC spokesman declined to comment.

As the new rules' effective date draws near, some companies have raised concerns that they could become targets of class-action litigation or regulatory action if their initial valuation estimates turn out to be wrong. The bulletin is expected to stop short of granting companies formal "safe-harbor" protection against future litigation over their methods of reporting options-related expenses. However, its provisions are designed to ease companies' worries by spelling out that there rarely will be situations where there is only one right answer in estimating the value of a given company's options, people familiar with the matter say.

In preparing the bulletin, the SEC's staff also sought to head off any criticisms by FASB opponents that regulators have failed to adequately study whether methods for measuring stock-option values are reliable. Last week the SEC's office of economic analysis delivered a seven-page memo to SEC Chief Accountant Donald T. Nicolaisen summarizing its findings on the subject.

The five authors of the March 18 memo concluded that the issues companies will face in estimating option values "are not unusual and indeed arise in other areas of accounting and finance." Additionally, they wrote that companies "have identified suitable methods for estimating future outcomes and obtaining reliable value estimates" and that "economists have developed methods for valuing employee stock options that are reliable and appropriate for use by companies in complying" with the new rules.

One example of a shortcut the SEC staff is expected to bless stems from provisions in the new rules that require companies in some circumstances to treat stock-option pay initially as part of inventory; under generally accepted accounting principles, labor costs are a major component of inventory values. According to people familiar with the SEC staff's efforts, the bulletin is expected to advise companies that they will be allowed to make end-of-quarter adjustments to their financial statements to estimate the amount of options-based labor cost that should be included in their inventory accounts. In doing so, people familiar with the matter say, the SEC staff is recognizing that most companies don't have the financial systems in place to track such costs on a daily basis.

Other areas to be addressed by the bulletin include guidance on making assumptions about future stock-price volatility and the expected length of time that employees will take to exercise their options -- both important parts of valuing stock options. The bulletin also is expected to contain sections on disclosure requirements and accounting for income-tax effects of stock-based compensation, as well as guidance for companies registering their shares on U.S. exchanges for the first time, among other things.

Write to Jonathan Weil at jonathan.weil@wsj.com¹