Eight employees from ‘‘a cross section of the firm’’ were dismissed, leaving 20.

Henry, in an e-mail to the Globe, said, ‘‘The company has been overstaffed for some time relative to its size.’’

As recently as 2004, Henry’s company had about $2.5 billion under management. Its current total under management is $188 million.

Henry said in his e-mail that the company also co-manages another $200 million with other firms.

Founded in 1982, John W. Henry & Co. manages or co-manages seven hedge funds of futures and commodities.

Hedge funds are lightly regulated investment vehicles that can own exotic securities.

The firm handles money for large institutional investors such as retirement plans, insurance companies, and wealthy families. It has been known for volatile returns, with wide swings in performance from year to year.

Although Henry’s company had an exceptional year in 2008, with its larger funds earning returns from 40 to 90 percent, its performance has fallen off in 2009. Those same funds are down between 6 and 21 percent from Jan. 1 to Oct. 31.

The dramatic shrinkage of the company’s assets, however, appears to have happened during the financial crisis last year. Investors who were scrambling to get cash out of their investments had easy access to their holdings at Henry & Co. Unlike other hedge funds, which were locking in investors for six months or longer when markets were falling, Henry & Co. allowed investors to withdraw their money on relatively short notice.

The son of an Arkansas farmer, Henry turned his knowledge of crops into a science of betting on futures — whether the price of commodities like soy beans will rise or fall.

His firm’s trading strategies are based on complex mathematical models he developed to follow price trends, replacing gut instinct with discipline in the investing process.

Historically, his funds do well in years when the mainstream markets — stocks and bonds — do poorly. He is known to personally keep close track of various markets, whether at home or in the office, through the day and into the night.

Hedge funds that invest in futures, like Henry’s, are roughly flat this year even though the stock markets rose robustly, according to Greenwich Hedge Fund Indices, which tracks performance. Futures had the worst performance of the hedge fund categories tracked by the group in 2009.

But hedge funds that invest in futures have fared better when the results are considered over time. The three-year average annual return on futures is 11.3 percent, better than most other hedge fund strategies.

A Red Sox spokeswoman declined to comment on the state of Henry’s business or its impact on the ball club’s finances.

Beth Healy and Robert Gavin of the Globe staff contributed to this report. D.C. Denison can be reached at denison@globe.com.