The windfall gain is the latest in a series of insider transactions by executives, coinciding with a year of stellar stock market returns. Earlier this week, Microsoft CEO Satya Nadella dumped half his holdings in the software giant. 

According to calculations by the Wall Street Journal, Musk topped the double-digit billion mark on Thursday based on the latest filings to the Securities and Exchange Commission. 

The Tesla boss plans to sell 10% percent of his stake, billed by Musk as a means of paying taxes amid continued pressure from U.S. lawmakers like Sen. Bernie Sanders that billionaires pay “their fair share.” Musk has responded brusquely to the progressive senator, tweeting at one point, “Want me to sell more stock, Bernie? Just say the word.”

Musk does not pay any tax on his income as Tesla CEO. Unlike his finance chief Zachary Kirkhorn, he doesn’t earn a base salary.

Instead, at his own request, Musk is awarded solely stock-based compensation by the company’s board. That means taxes accrue in the form of capital gains only when he liquidates a portion of his holdings.

In order to finance his lifestyle, he has reportedly been pledging his shares to creditors in order to borrow against the value of his stake in the company. This amounted to roughly 22% of Tesla’s outstanding stock at the end of last year.

In addition to the 227 million shares he held in Tesla, he also holds call options on another 22.9 million shares. The board’s independent directors awarded Musk these contracts in 2012 as part of a comprehensive multiyear incentive package. 

At the time, Tesla’s market cap amounted to just $3.2 billion, a far cry from the $1 trillion–plus it trades at today. Now, almost 10 years later, the options are worth a fortune thanks to the exceptionally low strike price of $6.24, more than a 99% discount to Thursday’s closing price of $1,084. 

These options must, however, be exercised by Aug. 13 of next year otherwise they expire and Musk forfeits billions. 

Record insider selling

According to SEC filings, Musk has purchased 10.7 million shares with the overwhelming bulk promptly turned around and sold in dozens of small transactions since Nov. 8.

That means he’s nearly halfway through exercising the options package. Until Musk finishes the cycle of transactions, the pending stock sales will continue to exert downward pressure on the stock.

Fortunately for investors, the fundamental strength of Tesla’s EV business versus its peers has only gained of late as legacy carmakers continue to struggle, not just with the undisputed market trend toward zero-emission cars, but with the semiconductor shortage. Consequently, Tesla shares trade only roughly 11% lower than the $1,222 closing price prior to when Musk announced his intentions on Nov. 6.

Musk and Nadella are not the only CEOs looking to cash in on the central bank–induced liquidity boom in equity markets that has caused a number of valuation indicators to flash red.

Brian Silverman, director of research at InsiderScore/Verity, estimates corporate insiders have dumped stock at the highest pace on record. As of Monday, the figure hit a record $69 billion in total before the year even ended. 

This represents an increase of 30% over 2020 and a whopping 79% versus a 10-year average, according to InsiderScore/Verity, which excludes sales by large institutional holders.