According to Nielsen Music, Michael sold 476,000 albums and songs in the week ending 29 December compared to 17,000 the week before - an increase of 2.6 per cent.
Of those sales, solo sales accounted for 429,000 - an increase from 16,000 the previous week.
The singer’s music with Wham! sold 103,000 units the same week, up from 5,000 the week before.
Michael was found dead at his home in Oxfordshire, England, on Christmas Day aged 53.