The brothers, who are the main members of Oasis, Britain's most popular band since the Beatles, were a new entry in the list, published yesterday.They went in at joint 461st position, with an estimated wealth of pounds 40m.
However, the Sunday Times says it errs on the side of caution when calculating a person's worth - using indicators such as land, property, racehorses, art treasures or shareholdings - so the figure should therefore be regarded as conservative.
Contributions to the Gallagher's fortune came from the band's two LPs, which stayed in the charts for years after they were released, a series of No 1 singles and concerts which included the Knebworth weekend, where they played to 250,000 fans over two days, in a concert which became an instant legend, on a par with Woodstock and the Beatles at Shea Stadium. Five per cent of the UK's population - three million people - applied for Knebworth tickets.
The band's spokesman would not put a figure on the brothers' true wealth, but said: "The current claims that Oasis have earned themselves pounds 40m are rubbish.
"The band has worked very hard for the past five years and has certainly been very successful. But to say they have earned themselves millions each is totally wide of the mark.
"It is not exactly clear how this figure has been arrived at, but it has certainly been done without consulting the people that would know - the band, the management and the record company."