Portfolio Import Accuracy
We compared automatic imports against our own records across a year. The errors were consistent and in predictable places.
Portfolio trackers import transactions automatically and produce tax reports. We compared their output against a manually maintained record.
The method
A year of transactions recorded manually at the time: date, type, assets in and out, local currency value at the moment, fee, platform.
Then the same period imported automatically into three trackers, and the results compared line by line.
Where the imports were wrong
Transfers between our own wallets recorded as disposals. The most common error and the most consequential, because it creates taxable events that did not occur.
The tracker cannot always tell that two addresses belong to the same person. Manual tagging fixes it and requires noticing.
Missing transactions from a platform we had stopped using. The export did not include them and neither did the import.
Incorrect local currency values for swaps, where the tracker used a daily average rather than the rate at the moment.
Staking rewards aggregated rather than recorded individually, which loses the per-receipt valuation that some jurisdictions require.
Fees not separated from the transaction amount in some imports.
Where they were right
Straightforward buys and sells on a single connected venue imported accurately and consistently.
The errors clustered in exactly the categories that are hardest to reconstruct manually, which is unfortunate rather than surprising.
The conclusion
Use a tracker for convenience and keep your own record as the source of truth.
The only way to notice an import error is to have something to compare against. Without a parallel record, the tracker’s output is unverifiable and it is what you would file.
The eight fields
Date and time, type, asset out and amount, asset in and amount, local currency value at that moment, fee, platform, note.
Ten seconds per transaction, at the time. The local currency value is the field that cannot be reconstructed accurately later and the one that matters most.
The access level
Connect trackers with read-only API keys. Never trading permission, never withdrawal permission, never a recovery phrase.
A tracker holding your complete portfolio and history is a valuable target, and several have been breached. The data leaked is precisely what an attacker wants for targeted phishing.
What makes reconciliation easier
A complete downloadable history from a single venue rather than partial exports from several.
Platforms publishing a full export, such as a platform we ran a full withdrawal through, turn the annual reconciliation into a short job rather than a reconstruction.
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