Incorrect Cost Basis for USDC Sale

I sold some USDC on Coinbase, why does it think that I gained ~$630 dollars on this sale? It’s a stablecoin whose price doesn’t fluctuate

It also will not let me change the cost basis of the transaction

You ever get a response? Same issue here and never any reply. Cost basis matches fine so not sure how I could even fix it.

Maybe they are pulling some “global average” price feed? I know Delta app has me with gains or losses on stablecoins that really doesn’t make sense, but stablecoins aren’t really like money market funds with a stable NAV per se. I saw the same thing happen with PAX when I owned it…gains/losses.

Also, did you have any interest for your USDC on Coinbase? That could also be messing around with your cost basis, especially is the price feed issue comes into play. I do find it odd you can’t change or adjust the cost basis, though. Can you delete fully and just put in a manual trade, instead of trying to adjust?

Seems like all of these crypto tax software programs are 50/50 on accuracy, unfortunately. Delta app has issues and the new, free, that needs a lot of work. Ha. Good luck.

Yeah it’s super confusing but basically an earlier trade somehow thought I gained the delta, roughly 600 USDC, for a 0 cost basis, so when I “fixed” that trade by manually switching it to have a ~600 cost basis, this trade was “fixed”.