Cost basis (cost of acquisition) of a disposed asset is calculated automatically by Koinly based on your previous transaction history and Settings selected. Koinly computes all the previous transactions involving the asset and applies the cost basis calculation method you selected to derive the cost basis.
☝️ Cost basis on a disposal is computed automatically - you cannot edit it
What if the cost basis is wrong?
Review the transactions that led to this disposal as those transactions are what Koinly used to calculate the cost basis. Possibly, there's an error in historical data that is causing the calculation to be implausible. Fixing this error (on historical transactions) will trigger Koinly to recalculate the cost basis on the trade in question.
To assess Koinly's cost basis calculations, see: