Those soaring chief executive bonuses may be trending downward, according to a new study of 178 companies with annual revenues of more than $1 billion.

The median value of such bonuses tied to annual performance plans for 2007 fell by 18.6 percent, according to a study completed in March. Equilar, a Redwood Shores, California, executive compensation benchmarking company, gleaned the information from new compensation data required by the Securities and Exchange Commission.

Fewer companies were handing them out, too: 70.4 percent last year compared with 77.5 percent in 2006.

Even so, the overall amount of C.E.O. bonuses in fiscal 2007 grew — albeit a minuscule 1.4 percent over the prior fiscal year. The overall bonus takes into account both discretionary awards and cash payouts from annual and multiyear performance plans.

The aggregate value of C.E.O. bonus compensation — the bulk of which is delivered through annual performance awards — fell by 4.7 percent. Annual performance-based payouts led the decline because they accounted for 62.8 percent of aggregate bonus compensation last year.

Equilar also looked at executive 10b5-1 stock trading plan disclosure for the past three years, 2005-2007. The plan allow executives to set up predetermined sell prices or sell dates in order to avoid accusations of insider trading.

The plan is often used as a defense for amazingly fortuitous stock sales by top executives, such as Angelo Mozilo, C.E.O. of lender giant Countrywide, who said his stock sales last year — prior to the company's troubles with subprime mortgages — were part of a pre-set sales arrangement.

From 2006 to 2007, Equilar found that the stock trading plans went up in popularity, with 5.5 percent more eligible company officers opting for them — but not as much as the prior period, from 2005 to 2006, when the total number of executives opting for pre-arranged sales jumped by 31.2 percent.

So last year, nearly one-third of Fortune 500 companies had at least one qualified executive using such a plan — up from 28.7 percent of companies the year before.

by Elizabeth Olson