Rebuilding Three Years of Crypto Trades After a CRA Letter

The situation

Kenneth sold real estate in Oshawa and the surrounding area. Winnie worked as a paramedic. Together they owned their home and a small rental property they had bought a few years earlier, partly funded by proceeds Kenneth had pulled out of a cryptocurrency account. Kenneth had been trading crypto as a side interest since well before that purchase — buying and selling across three different exchanges, moving coins between wallets, occasionally cashing out to cover a slow month in real estate commissions.

Their returns were prepared each year by Pratheep, a bookkeeper they had used since their first rental property. Pratheep worked from whatever summary numbers Kenneth handed over — a rough annual gain figure, sometimes just an estimate typed from memory. Nobody had ever pulled a full transaction history from the exchanges themselves. For a few years that was fine. Then one of the three exchanges Kenneth had used shut down its Canadian operations, wiped its historical statements after a retention period, and left him with no way to log back in and download anything.

The letter from the Canada Revenue Agency arrived the following spring. It proposed to reassess three prior tax years, citing cryptocurrency transaction data the CRA had obtained directly from exchanges through international information-sharing arrangements — the same channels that let tax authorities match reported income against records the taxpayer never provided. The number in the letter was alarming: it treated a large share of Kenneth's total trading volume as unreported income, without any credit for what he had originally paid for the coins he sold.

What the review found

The first job was figuring out how bad the gap actually was. The CRA's proposed figure assumed the entire value of Kenneth's crypto disposals was taxable gain, because it had no record of his purchase prices — his cost basis, the amount originally paid for an asset, which gets subtracted from the sale price to calculate the actual gain. Without cost basis, every dollar coming out of an exchange looks like pure profit. That is rarely true, and it was not true here, but proving otherwise meant reconstructing years of trades exchange by exchange.

Two of the three exchanges still had accessible statements, and those were downloaded in full. The third — the one that had shut down — was the problem. Its data no longer existed on the exchange's side. Reconstructing those transactions meant cross-referencing the wallet addresses Kenneth still had access to against public blockchain records, matching transaction timestamps to historical price data for the coins involved, and rebuilding a defensible cost basis transaction by transaction rather than relying on any single clean export.

A second issue sat underneath the missing records. Some of Kenneth's activity looked less like passive investing and more like active trading — frequent buying and selling, short holding periods, a clear profit motive. That distinction matters under the Income Tax Act: gains on investments held for appreciation are generally taxed as capital gains, with only half the gain included in income, while gains from a pattern of buying and selling that amounts to carrying on a business are taxed as fully includable business income. CRA's letter had treated the bulk of Kenneth's activity as business income. Some of it plausibly was. Some of it — coins he had bought and simply held for a long stretch before selling — had a real argument for capital treatment instead, and that argument was worth pursuing transaction by transaction rather than conceding across the board.

What we did

1. Requested more time before responding formally. CRA reassessment letters come with a response deadline, and rebuilding years of missing transaction history inside that window was not realistic. An extension request, made early and with a clear explanation of what was being reconstructed and why, bought the weeks needed to do the work properly rather than filing something incomplete under pressure.
2. Pulled every surviving record from the two active exchanges. Full transaction exports, not summaries — deposit and withdrawal history, trade-by-trade pricing, and transfer records showing coins moving between Kenneth's own wallets, which matters because moving crypto between your own accounts is not a taxable disposition and should never be counted as one.
3. Reconstructed the closed exchange's history from the blockchain itself. Kenneth's wallet addresses were cross-checked against public blockchain explorers to rebuild a transaction timeline, then matched to historical price data to establish a defensible cost basis for coins where no exchange statement would ever exist again.
4. Separated capital transactions from business-pattern trading. Working through the reconstructed timeline, the coins Kenneth had bought and held for extended periods before selling were distinguished from the shorter-term, higher-frequency trades that more clearly reflected an intention to profit from active trading. Each category was documented with the reasoning behind its classification, because CRA does not accept a bare assertion — it wants to see the pattern the classification is based on.
5. Prepared a full submission responding to the reassessment. The reconstructed cost basis, the corrected capital-versus-business breakdown, and a request for penalty relief were submitted together, with Pratheep's original estimates set aside entirely in favour of the rebuilt figures.

The outcome

The reconstruction did real work. CRA's original proposed reassessment treated close to $140,000 of Kenneth's crypto disposals as fully taxable, with no cost basis credited anywhere. Once the rebuilt records were submitted, the recalculated gain — after subtracting actual cost basis and after a meaningful share of the activity was accepted as capital rather than business income — came down to roughly $85,000 in additional tax owing across the three years, plus interest that had been accruing since the original filings.

That was still a hard number. It was not a result where the family walked away owing nothing, and it should not be described as one. What the reconstruction avoided was the much larger exposure sitting inside CRA's original letter, and it also supported a request to reduce the penalty CRA had proposed. Because Kenneth had used a preparer and had responded to the reassessment cooperatively and with genuine supporting records rather than disputing the numbers on principle, CRA agreed to a reduced penalty rather than the higher gross-negligence-level penalty that applies when a taxpayer is found to have knowingly or recklessly misreported.

One door had already closed by the time the letter arrived. CRA operates a voluntary disclosures process that lets taxpayers correct past errors on more favourable terms — but only if they come forward before the CRA has already started looking at them. Once Kenneth received the reassessment letter, that door was shut; the disclosure would no longer have counted as voluntary. Had the family rebuilt their records and filed a correction a year earlier, before any letter arrived, the outcome would very likely have involved less tax, less interest, and a much smaller penalty, if any. That gap — between what proactive correction could have achieved and what a reactive defence actually achieved — was the real cost of relying on rough annual estimates for years.

What you can learn from this