I wish I understood the method behind the madness of the way Fidelity monkeys with the number available on any given day...
Its not like 150,000 shares magically disappeared from being available overnight.
I think that they make sure they have enough shares to cover the perceived demand, so "low availability" today could be an indication of their perception of the demand for shorting. Low demand for shorting should be good for SP. This is just my speculation, of course...
BTW, grabbed another share in the Brockerage portion of my 401K at $298. (no more funds available, the rest of them are already in TSLA)