NEW YORK (AFP) - A guitar once owned by Grateful Dead legend Jerry Garcia on Wednesday raised more than US$3 million (S$4.2 million) at an auction to support a leading civil rights group in the US.

Known as Wolf, the custom-made electric guitar was a constant concert companion of Garcia until the jam rock icon died in 1995.

The original buyer put the guitar back on auction to raise money for the Southern Poverty Law Centre which wages legal battles against hate groups.

At a charity concert in New York, Mr Brian Halligan, CEO and co-founder of marketing firm HubSpot, paid US$1.932 million, including the premium.

An anonymous charity matched his pre-premium US$1.6 million bid, bringing the total donation to US$3.2 million.

The Grateful Dead officially disbanded last year with a series of farewell concerts but the fan base remains fervent.