The private board that writes U.S. accounting rules unanimously agreed this week that companies should be required to treat stock options for executives and employees as expenses, a key show of support for a measure opposed by high-tech industries and some members of Congress.

The Financial Accounting Standards Board, meeting at its Norwalk, Conn., headquarters, determined that options "are goods and services that are being exchanged and you must recognize it just as you would other goods and services," spokeswoman Sheryl Thompson said.

The board will now move on to what Chairman Robert Herz has acknowledged will be its most difficult task: determining how to value options. The board said it expects to have a new rule in place sometime next year.

Current rules do not require companies to count options as expenses, only that they disclose -- in the footnotes to financial statements -- what earnings would have been had options been an expense item. Using one of several valuation methods, Microsoft Corp. has said its earnings in its last fiscal year would have been reduced by about 32 percent if it had to expense options.

But shareholder groups have criticized the practice of not expensing options, arguing that in a series of high-profile corporate failures, options created an incentive for executives to use accounting tricks to inflate profits, thereby boosting stock prices and increasing the value of their own options.

Federal Reserve Chairman Alan Greenspan has said he supports the expensing of options.

The accounting standards board attempted to mandate an expensing policy in 1993 but backed down after Congress threatened to strip it of its power.

Some members of Congress are again trying to stop the effort.

Rep. David Dreier, R-Calif., chairman of the House Rules Committee, and Rep. Anna Eshoo, D-Calif., introduced a bill last month that would prohibit the Securities and Exchange Commission from enforcing a new stock-option rule until it studied the issue for three years. The bill also would require that the secretary of commerce spend a year studying the corporate and economic impact.

And Tuesday, Sen. Barbara Boxer, D-Calif., said she and Sen. John Ensign, R-Nev., plan to introduce a similar bill when Congress returns next week from its spring recess.