According to a US regulatory filing, Cook sold 2,65,000 Apple shares worth $121 million, Business Insider reported late on 29 August.
Nearly $64 million of the share options were withheld for tax reasons and Cook took home over $57 million.
The stock awards were in addition to his salary and bonus scheme.
Cook earned $12.8 million last year, $3 million as base salary and a $9.3 million cash bonus, rising 46 percent.
"Cook's net worth is estimated to be $625 million," the report said.
Earlier this month, Apple became America's first publicly-traded company to hit the $1-trillion milestone.
The company is reportedly introducing at least three new iPhone models next month which may include a considerably larger version of the iPhone X and a less expensive version.