NEW YORK (CNN/Money) - Office productivity will begin a 16-day plunge next Tuesday, when workers will be too busy watching the NCAA basketball tournament on their office computers to get much work done, according to a new study.

March Madness could cost American companies $889.6 million in lost work, according to Challenger, Gray & Christmas, Inc., a significant jump from the 2004's $765.7 million tally. Work performance will plummet as workers remained glued to their monitors, watching the games online for the first time, the study said.

The tournament, played at basketball arenas nationwide through April 4, will be broadcast by CBS and will be available through three Web sites: cstv.com, cbssportsline.com and ncaasports.com.

Challenger arrived at $889.6 million by taking a figure from Websense Inc., an Internet filtering service that estimated in 2003 that college basketball fans spent about 90 minutes a week, or about 13 minutes a day, trolling through basketball Web sites. Based on the average hourly pay of $17.96, Challenger calculated the loss at $3.89 per worker. Multiplied by 14.3 million, the NCAA estimate of total for working fans, the projected loss in productivity is $55.6 million a day, or $889.6 million for 16 days.

John A. Challenger, CEO of the firm that performed the analysis, suggested that companies take charge of their workers by coordinating office pools and monitoring their employees' Web activities more tightly.

"Companies may want to expand their Internet blockers to include college basketball sites and they may want to encourage workers to refrain from watching entire games at their desks," said Challenger, in a prepared statement. "However, there is no reason a company cannot institute a companywide pool, which employees can enter for free and winners receive some type of gift, such as an extra day off or a restaurant gift certificate."

Most NCAA betting pools are in the workplace, according the to the FBI. The agency forecasts that NCAA gambling will total $3.5 billion, with 52 percent coming from millions of office pools, Challenger's study reported.