The X Factor judge and creator moves up from his number 11 position in last year's list to overtake Elton John, Mick Jagger, Sting and Keith Richards.
The list is topped by Zomba Records co-founder Clive Calder, who has amassed a personal fortune of £1.3 billion and returns to the summit following the UK departure of Edgar Bronfman, who headed last year's list with a £1.64 billion fortune.
Classical singer Katherine Jenkins managed to retain her number one placing on the Top 20 Young Music Millionaires list, increasing her personal fortune by £2 million to £13 million.
She faced tough competition from X Factor judge and Girls Aloud star Cheryl Cole, who moves up from number four to two with her £12 million bank balance. Cole is joined by Leona Lewis and Katie Melua, who are also placed joint second after building up £12 million fortunes.
Adele is the highest new entry on the list landing at joint ninth place with £6 million following the huge success and sales of her first two albums and live shows.
The remaining members of Girls Aloud - Nadine Coyle, Sarah Harding, Nicola Roberts and Kimberley Walsh - come in at joint 14th with £5 million each.
The 23rd annual Sunday Times Rich List will be published in this weekend's Sunday Times.
See the top ten placings for each list below:
Top Ten Music Millionaires
1. Clive Calder - £1.3 billion
2. Lord Lloyd-Webber - £680 million
3. Sir Cameron Mackintosh - £675 million
4. Sir Paul McCartney - £495 million
5. Simon Fuller - £375 million
6. Simon Cowell - £200 million
7. Sir Elton John - £195 million
8. Sir Mick Jagger - £190 million
9. Sting - £180 million
10. Keith Richards - £175 million
Top Ten Young Music Millionaires
1. Katherine Jenkins - £13 million
2=. Cheryl Cole - £12 million
2=. Leona Lewis - £12 million
2=. Katie Melua - £12 million
5. Joss Stone - £9 million
6=. Charlotte Church - £8 million
6=. Craig David - £8 million
8. Paolo Nutini - £7 million
9=. Adele - £6 million
9=. Lily Allen - £6 million
9=. Natasha Bedingfield - £6 million
9=. Duffy - £6 million
9=. Amy Winehouse - £6 million