It's not just Elon Musk: Here's who else at Tesla has been selling the stock

New York(CNN Business) Just days before his brother started selling billions of dollars worth of Tesla shares, Kimbal Musk, a Tesla board member, sold $108 million worth of his own stock in the company.

The dollar value of his sale is dwarfed by his brother Elon's sale of $5.7 billion worth of Tesla stock from Monday through Thursday this week. But it represented a much larger percentage of his holdings in Tesla (TSLA) -- about 15% of Kimbal's stake in the company. Elon's stake has declined by only 3% so far through his sales through Thursday.

Although Elon Musk's sales were the first time he sold any Tesla stock since 2016, Kimbal Musk has been selling his own shares on a regular basis. So have many other top executives and board members at the world's most valuable automaker.

Robyn Denholm, the company's chair, has been selling regularly shares since she got the job overseeing the board in late 2018. In the last two years, each time she exercised options she received as part of her compensation, she immediately sold all the shares she had just acquired.

Zachary Kirkhorn,Tesla's so-called Master of Coin, who used to have the more standard title of chief financial officer, has also been selling shares regularly.

Leaving money on the table

All three are probably the poorer for doing so. Tesla shares had an incredible run these last two years, rising nearly 2,000% since the company surprised investors with a profitable third quarter in 2019. That kicked off a string of profitable quarters. Before that October 2019 report, many investors worried that the company might be facing a cash crunch.

That stock ride has made Tesla only the sixth US company to reach a valuation of $1 trillion, achieving a market value greater than the combined market cap of the 12 largest automakers on the planet and making Elon Musk the richest person in the world.

Many insider sales are made to diversify their holdings and don't necessarily predict the direction of the stock. In the case of Tesla insiders, diversifying wasn't necessarily the best strategy.

"The irony is they left hundreds of millions on the table by selling early," said Daniel Ives, tech analyst with Wedbush Securities.

Kimbal Musk's sales

Kimbal Musk has sold 525,00 shares on a split adjusted basis since October 2019, receiving $189 million as a result, for an average price of $360 a share. If he still owned all those shares, they now would be worth $369 million more than what he received. And he would have just more than twice as many shares as he currently holds.

Some of Kimbal Musk's sales were made using a "Rule 10b5-1 trading plan," an SEC rule that allows company insiders to sell shares on a pre-arranged schedule so they can't be accused of trading on news about the company. He has also sold some shares in which the filing doesn't mention such a plan.

For example, in February 2021 Kimbal Musk sold $25.6 million in Tesla shares without the filing mentioning any trading plan. Telsa shares suffered a 33% slide over the next four weeks. It doesn't look like anything happened after the sale that wasn't public information at the time that he sold, but he anticipated the market pretty well, at least in the short-run.

Tesla shares have made up that lost ground and more since that sale, when his shares sold for an average price of $852. Now they are trading over $1,000, even with the recent slide brought on by his brother's stock sales.

Last week's sales by Kimbal Musk, just before his brother started selling shares, did not mention a Rule 10b5-1 trading plan.

Zachary Kirkhorn's sales

Virtually all of Kirkhorn's sales have been through Rule 10b5-1 plan trades, although some additional sales were performed by the company to pay the withholding taxes he owed on exercised stock options that are part of his compensation.

In most months, he's sold between 750 shares and 1,250 shares on a split adjusted basis, which, during the the last two years, have amounted to 25,250 shares, at an average price of $503 a share, or about half of their current value. That brought him $12.7 million.

Robyn Denholm's sales

Denholm's filings over the last two years do not mention any trading plan. She has sold nearly 412,000 shares of Tesla on a split-adjusted basis, leaving her with the same stake of 5,000 Tesla shares that she had two years ago just before shares started their rise.

The shares that she held came from exercising stock options that cost her a fraction of their market value, generating a $200 million profit. She would have done much better hanging onto the shares she acquired and immediately sold, which would have been worth $438 million.