Tesla’s Frankfurt-listed shares underwent a downfall of about 9% in early trading on Monday as investors looked for Chief Executive Elon Musk’s proposed sale of a tenth of his holding in the electric-carmaker following his Twitter polls.

On Saturday, Elon Musk took to Twitter stating that he would sell 10% of his stock if netizens approved the proposal. The poll attracted over 3.5 million votes while 57.9% of the voters answered with “yes.”

Much is made lately of unrealized gains being a means of tax avoidance, so I propose selling 10% of my Tesla stock.

Do you support this?

— Lorde Edge (@elonmusk) November 6, 2021

Previously, Musk mentioned that he would have to exercise a large number of stock options in the upcoming three months, which would result in a big tax bill. Besides, selling some of his stocks would free up his funds to pay taxes.

“I was prepared to accept either outcome,” said Musk after the polling concluded. Market participants expected that speculators would try to front-run his selling.

I will abide by the results of this poll, whichever way it goes

— Lorde Edge (@elonmusk) November 6, 2021

Reportedly, till June 30, Musk’s shareholding in Tesla amounted to 170.5m shares, and selling 10% of it would close to $21bn based on Friday’s close, as per Reuters.

Musk owns a 23% stake in Tesla, including stock options. Tesla is regarded as the most valuable car company. In three months to November 4, Tesla sold $259.62m-worth of shares, apart from depositions of indirectly held shares, according to Refinitiv Eikon data.

Musk straw polls came after a proposal by U.S. Senate Democrats to tax billionaires stocks and additional tradeable assets to aid finance President Joe Biden’s social spending agenda and fill a loophole that allowed them to put off capital gains taxes indefinitely.

“The last thing you do when offloading a massive exposure is to reveal your hand,” said Chris Weston, the head of research at broker Pepperstone in Melbourne. “The buyers tend to step away when you have an overhang like this, but this is no ordinary story and is Musk’s way of getting back at the proposal to tax the elite with gains on unrealized profits.”

Late in October, Tesla failed a trillion dollars in market capitalisation, thus becoming the fifth US company to join Apple, Microsoft, Amazon, and Alphabet.

“I’d be looking for clients to flip to shorting fairly aggressively, although hold periods would be very short-term in nature,” Weston added.