In the weeks since
Their Greatest Hits was certified platinum for the 29th time back in 2006, meaning that sales of the compilation surpassed 29 million copies in the United States. Meanwhile, Thriller was last certified in March, when it passed 28 million. Demand for physical copies of Jackson albums (an estimated 82 percent of his sales have been actual CDs) have ramped up the number of copies of Thriller in circulation, and the RIAA believes that said demand has brought the number up to 29 million.
That does not necessarily mean that Thriller has sold 29 million copies, as the RIAA's certification process is based on the number of albums shipped to stores, not necessarily the number actually scanned and sold. But based on the rabid consumption of Jackson's music in the past few weeks and the hard numbers released weekly by SoundScan, it's doubtful that there is much distance between the number of CDs shipped and the number sold. If the pace continues, Thriller will become the first album to go triple diamond, meaning 30 million albums sold.
The RIAA's certifications are simply a formality, though, as Jackson's Thriller is already recognized as the top-selling album according to worldwide sales. Though numbers vary, it's reasonable to estimate that the album has moved 110 million copies worldwide since its 1982 release. As a comparison, the Eagles' Their Greatest Hits has moved an estimated 42 million — a formidable number for sure, but less than half of Jackson's total.