Getty Images/Chip Somodevilla
That's a lot of money to spend, even for a company with $146 billion in cash.
For some context, $16 billion is more than the most recent valuation for Twitter. It's more than 3X the size of BlackBerry's market cap. It's more than Google spent to buy Motorola. Independent analyst Horace Dediu called it Apple's largest acquisition ever.
DeWitt says Apple bought 36 million shares at an average price of $444 a share. This suggests the company was buying high. Shares were under $400 at times in July and April.
Despite Apple's stock buying spree, shares were down 4.6% from April 1 to July 1.
Imagine what would have happened to Apple's stock if it weren't buying all quarter. How low would it be?