Calculation of cost basis for options trades

david.d's Avatar


05 Dec, 2020 07:45 PM

I recently opened a covered-call position against my Tesla stock, selling one Dec. 24th contract at $52.00 per share. When I downloaded the transaction from Vanguard, it initially appeared as 1 share at $5200, representing the single contract, which recast as 100 shares at $52. So far so good.

But here's the interesting part: the original download showed a cost basis of -$1.92, which seemed strange as it didn't relate to anything else. Even worse, though, when I recast the transaction, it multiplied by 100, both per share and overall, giving me a supposed cost basis of -$192.31 PER SHARE for a total of -$19,230.77! What?

Where are these numbers coming from? Please explain. I'll be happy to upload additional data, if someone can tell me what might help.


  1. System closed this discussion on 06 Mar, 2021 07:50 PM.

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