The estate of George Michael—who died of heart failure on Christmas Day at the age of 53—is valued at $125 million, People reports. But that number looks likely to increase in the wake of his death. According to Forbes, both Michael's solo work as well as the WHAM! back catalog are seeing a surge in popularity. In the 24 hours after his death, plays of Michael's songs on Spotify increased by 3,100%. And 10 of his songs suddenly appeared in iTunes' top 100 list. “The music already, in terms of streaming and downloads, has increased significantly since news of his death,” attorney Donald David tells People. David says the posthumous increase in popularity could add up to $10 million to Michael's estate over the next two years. (More George Michael stories.)