Executive pay at the largest companies in the U.S. hit a sixth straight annual record in 2021, as the median pay packet for leaders at S&P 500 companies rose roughly 12% to $14.7 million, according to an analysis from the Wall Street Journal.

But the highest-paid executives might not be who you expect.

For example, Elon Musk, the world’s wealthiest man, was the lowest-paid CEO in 2021, receiving a total salary of $0 from Tesla Motors for the second year in a row.

In 2018, however, Tesla awarded Musk a record-setting $2.3 billion pay package, including 12 tranches of stock options. In the years since, 11 of those 12 tranches have vested, potentially earning Musk $65 billion, and negating the need for regular pay.

Roughly two-thirds of CEO compensation comes in the form of stock or stock-option awards, the Journal says, with the top 25 highest-paid CEOs claiming 78% of total compensation in equity.

Receiving stock options as compensation confers earnings over several years rather than all at once, which can make the difference between being “well paid” and being fabulously wealthy in any given year. In theory, paying executives in equity rather than cash creates a stronger link between CEO pay and company performance since a CEO’s stock options will earn more if the company’s share price goes up.

In 2021, the highest-paid CEO was Peter Kern, who took over as chief executive of online travel company Expedia Group in April 2020. Kern was awarded $296 million in compensation last year, almost entirely in stock options, which won’t begin vesting until 2024.

The rest of the top five earning spots were rounded out by technology, entertainment, and banking executives.

Second place was David Zaslav, CEO of Warner Bros. Discovery, with $246.57 million in compensation. According to the Journal, Zaslav’s pay packet includes a $203 million stock option that depends upon the company’s stock price doubling by December 2027—a feat that would add tens of billions of dollars in value for shareholders.

William McDermot of workflow management software firm ServiceNow is the third highest-paid CEO, with $165.80 million in compensation. Apple’s Tim Cook took home $98.73 million in fourth place—reportedly marking the first time Cook has been awarded equity as pay since he became CEO in August 2011.

JPMorgan Chase chief Jamie Dimon claimed the fifth spot, with $84.43 million in compensation.