So I learned I don't actually "own" TSLA shares, at least in the sense that we consider owning something in everyday language (like, how "I own my car," or "I own my clothes"). Read the fine print on your margin account application (page 15, "Add Options Trading and Margin to your Account," for Schwab clients). By opening an account with your broker, you have agreed to loan your securities to your broker at their whim and calling, whenever they feel like, without notifying you. Also, while "your" shares are out on loan, even though you get proxy instructions to vote in corporate elections, those shares voting power goes to the party currently lending your shares. Also, when your shares are being lent, the broker of course receives interest payment for lending, and is incentivized to keep the loan going for as long as possible, while you receive nothing, hahaha, not even your dividends.
You can't make this stuff up, it's all in the fine print.
Here it is from Schwab:
8. Loan Consent. You agree that Securities and Other Property held
in your margin account, now or in the future, may be borrowed (either
separately or together with the property of others) by us (acting
as principal) or by others. You agree that Schwab may receive and
retain certain benefits (including, but not limited to, interest on
collateral posted for such loans) to which you will not be entitled. You
acknowledge that in certain circumstances, such borrowings could
limit your ability to exercise voting rights or receive dividends, in whole
or in part, with respect to the Securities and Other Property lent. You
understand that for Securities and Other Property that are lent by
Schwab, the dividends paid on such Securities and Other Property
will go to the borrower. No compensation or other reimbursements will
be due to you in connection with such borrowings. However, if you are
allocated a substitute payment in lieu of dividends, you understand that
such a payment may not be entitled to the same tax treatment as may
have been applied to the receipt of a dividend. You agree that Schwab
is not required to compensate you for any differential tax treatment
between dividends and payments in lieu of dividends. Schwab may
allocate payments in lieu of dividends by any mechanism permitted by
law, including by using a lottery allocation system.