The sudden death of Grateful Dead leader Jerry Garcia on Wednesday casts a shadow over the future of one of the entertainment industry's most unlikely financial empires.

It is likely that the group will cancel the remainder of its lucrative North American tour and could even decide to throw in the towel as a concert attraction altogether, sources said. However, the band is expected to continue to enjoy strong sales of Grateful Dead merchandise.

A spokesman for the band said no decision about its future will be made immediately.

For much of its three-decade run, the psychedelic San Francisco rock band has reigned as the most successful draw on the concert circuit, raking in between $30 million and $50 million a year. The graying sextet was also recognized as a savvy group of capitalists, who aggressively exploited their own anti-Establishment image by marketing a wide array of authorized merchandise--from music to silk ties.

"In terms of longevity, the Grateful Dead is arguably the most successful rock act on the concert trail in the history of business," said Gary Bongiovanni, editor of Pollstar magazine, a leading concert trade journal.

The band has given birth to an entire generation of fans known as Deadheads who have purchased more than 20 million albums and spend millions of dollars each year snapping up a growing line of products from the Grateful Dead's mail-order catalogue. As his fans grew up to become lawyers and accountants, Garcia became such a household name that Ben & Jerry's even named an ice cream flavor, Cherry Garcia, after him.

But the Grateful Dead has profited most from its appeal as a live concert act. Over the past five years, Grateful Dead fans have forked over more than $225 million on concert tickets in North America. The band, which staged its last show on July 9 at Soldier Field in Chicago, sold $34 million in tickets during the first seven months of 1995 alone.

While no official decision about the band's future has been made, statements made in the past suggested that the group is not likely to continue its concert touring without its main draw. The 53-year-old Garcia had been hospitalized several times over the years for diabetes, exhaustion and drug-related illnesses. Following one episode in 1986, when the guitarist lay comatose in a hospital, the Grateful Dead implied at the time that the band would probably break up if Garcia or any other key member died.