If I had stock valued at $83 each and it went up to $90, and I purchased it at $90, would that decrease the value ? Or would it increase it?

It just means your two lots have different cost bases.

You calculate gain/loss when you sell.

Thank you

If I had stock valued at $83 each and it went up to $90, and I purchased it at $90, would that decrease the value ? Or would it increase it?