willow_hiller
Well-Known Member
The mechanics of option positions closing on a Friday, and the unwinding of hedging positions by market makers when those positions are closed leading to common Stock being bought or sold, actually naturally moves the stock price close to a round number where strike places are. It happens with every stock with large option trading activity, and the effect is amplified on Fridays with large amounts of option positions expiring. If you run the same analysis on other stocks with high levels of Options trading you will find the same pattern, it isn’t unique to Tesla. That doesn’t mean there aren’t attempts at manipulation of course, but the underlying trend for the stock to end a Friday close to a strike price is an underlying quirk of the system, not necessarily manipulation.
Good explanation, but it does seem like TSLA is slightly extraordinary in this regard.
Just ran it for the same dates for AAPL. Odds of a 5 on Monday-Thursday is 11.0%, with odds of a 5 on Friday being 9.3%. High p-value of 0.537 means the relationship is likely zero.
EDIT: Checked AAPL for 0s as well since they'll have fewer expiries ending in 5s. Odds of a zero on any day is 8.8% no matter Monday-Thursday or Friday, with a p-value of 1 indicating no relationship whatsoever.
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