New York ? As the American economy slowed to a crawl and stockholders watched their money evaporate, CEO pay still chugged to yet more dizzying heights last year, an Associated Press analysis shows.

The AP review of compensation for the heads of companies in the Standard & Poor’s 500 index finds the median pay package added up to nearly $8.4 million. That’s a comfortable gain of about $280,000 from 2006.

The 3.5 percent pay increase for CEOs came even as the landscape for both workers and shareholders darkened considerably and the economy was choked by a housing market in free fall, layoffs and soaring prices for fuel and food.

At the top of the AP list: John Thain, who took the reins of Merrill Lynch on Dec. 1, 2007. His $83 million pay package was supercharged by a signing bonus and other enticements that lured him from the New York Stock Exchange to lead the investment bank as it was suffering its worst-ever losses.

Collectively, the 10 best-paid CEOs made more than half a billion dollars last year. Yet half the members of this stratospheric club were leading companies whose profits shrank dramatically.

The AP examination of CEO pay in 2007 mined data from the 410 companies in the S&P 500 that filed compensation disclosures with federal regulators in the first six months of this year.

The AP’s formula, based on data from the past two years, adds up salary, perks, bonuses, above-market interest on pay set aside for later, and company estimates for the value of stock options and stock awards on the day they were granted last year.

The median salary figure of about $8.4 million means half the CEOs in the AP analysis made more than that and half made less.

There were some signs companies were pulling back on pay at the top: Out of the 316 companies in the AP survey that had the same CEO two years running, about two-fifths lowered the total pay package for their CEOs.

However, the primary culprit for some was falling stock prices that cut into the value of the shares included in pay packages.