Billionaire philanthropist MacKenzie Scott has reduced the size of her stake in Amazon .com by 42% since last year, Bloomberg News reported on Tuesday, citing a regulatory filing.

Scott, the former wife of Amazon founder Jeff Bezos , holds 81.1 million shares in the company, according to the latest disclosure dated September 30, down 58 million from a year ago, according to the news report.

Based on Amazon's closing price on Tuesday, the reduction is worth $12.55 billion.

Reuters could not independently confirm the filing.

A regulatory filing made with the U.S. Securities and Exchange Commission in Bezos' name said he beneficially owned more than 964 million Amazon shares as of September 30, including 81.1 million shares over which Bezos exercises sole voting authority.

Amazon did

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