Last Updated on April 16, 2026 by Patrick Camuso, CPA
Quick answer (read this first):
The short answer: No, you can’t fix crypto taxes without addressing prior years?. Cost basis is cumulative. Every year’s ending inventory becomes the following year’s starting point. Prior year errors, missing records, and misclassified transactions carry forward into every subsequent return until they are corrected.
What this means in practice: A taxpayer who attempts to report 2025 activity correctly without addressing 2020 through 2024 is calculating gains and losses from a defective starting position. The result may appear complete but it is not defensible.
What actually has to happen: Historical accounting must be reconstructed from the earliest period of activity forward before current year reporting can produce accurate, substantiated numbers.
The Most Common Question Before Engagement
The most common question we hear at Camuso CPA before a new client engagement in this space is some version of can the prior years be left alone and reporting begin fresh from this year forward?
Prior year activity is complicated, records are incomplete, exchanges have closed, wallets were never reconciled. The historical accounting work required to correct years of fragmented activity is substantial, and the appeal of establishing a clean starting point for current year compliance is understandable.
The structure of cost basis accounting does not permit it.
Why Prior Years Cannot Be Skipped
Cost basis in digital assets is not reset each year, it accumulates. Every acquisition creates a tax lot with a specific cost and acquisition date. Every disposal relieves one or more of those lots. Every transfer moves lots between accounts. The ending inventory at December 31 of one year becomes the opening inventory on January 1 of the next.
If a taxpayer misclassified a wallet transfer as a taxable sale in 2021, that lot was removed from inventory and replaced with a zero-basis lot at the receiving address. Every subsequent calculation that touches that lot is wrong, not because of anything that happened in the current year, but because the 2021 error is embedded in the inventory the current year is working from. If a taxpayer never recognized staking rewards as income in 2022 and 2023, those lots carry zero basis. When they are eventually sold, the gain calculation runs from zero regardless of how carefully the current year return is prepared. If a taxpayer used software that treated a bridge transaction as a nontaxable transfer in 2020 when it was actually a taxable disposal, the basis of the received asset reflects an incorrect carryover. That error compounds every year until it is identified and corrected.
The current year does not start clean. It starts where the prior year ended. And if the prior year ended with defective cost basis, the current year inherits that defect.
Revenue Procedure 2024-28 introduced an additional structural complication. Taxpayers who had been applying a universal pooling methodology prior to 2025 were required to transition to wallet- and account-level basis tracking, with a one-time safe harbor available to allocate unattached basis into specific wallet pools as of January 1, 2025. Taxpayers who did not complete that safe harbor allocation are still obligated to use per-wallet tracking for 2025 and subsequent years, but without the penalty protection the safe harbor provided. The result is a compounding problem since prior year basis errors carry forward into an accounting framework that now demands per-wallet precision, without the documented transition mechanism that would have established the starting position for each wallet.
What Form 1099-DA Changes About This
Before Form 1099-DA, the cumulative nature of cost basis errors was largely invisible. Software produced a gain and loss report, the taxpayer filed it, and the IRS had limited visibility into whether the underlying basis was accurate. Beginning with 2025 transactions, brokers are reporting gross proceeds directly to the IRS. When basis reporting for covered assets goes live for 2026 transactions, the IRS will begin receiving proceeds and basis data that it can match against what is reported on the return.
The compliance picture is further complicated by the existence of three independent records that describe the same economic activity which is the on-chain transaction record, the output of the taxpayer’s accounting software, and what the broker reports to the IRS on Form 1099-DA. None of these were designed to reconcile with each other. Each reflects different data, different timestamps, and different classification logic. Prior year errors that embedded in the software’s lot inventory will produce discrepancies when that inventory is used to calculate basis against proceeds the broker has reported.
The practical effect is that prior year errors that were previously invisible are now exposed whenever a disposition of an affected lot is reported. The longer they go unaddressed, the more disposals accumulate on top of a defective foundation.
What Reconstruction Actually Involves
Historical cost basis reconstruction is an evidentiary process governed by the best available evidence standard. It works through available records in priority order with exchange records and on-chain data first, then secondary sources including email confirmations, bank funding records, and platform support correspondence, then any contemporaneous taxpayer documentation. Where gaps persist after exhausting available sources, conservative assumptions are applied and memorialized in a formal assumptions register that can be produced under examination.
The output is a lot-level inventory schedule with every lot, its documented cost basis, its acquisition date, and its continuity across transfers that can be traced to evidence and carried forward as a defensible starting position for current and future year reporting.
The Audit Risk
Addressing prior years proactively is a risk management decision. The IRS has publicly stated that digital asset reporting non-compliance is widespread and has indicated that enforcement is a priority as third-party reporting infrastructure becomes operational.
The scope of an IRS examination in this space is broader than most investors expect. In active crypto audits, the IRS has been issuing information document requests that cover the taxpayer’s complete digital asset custody history, including all exchanges, wallets, and self-custody addresses ever used, routinely spanning more than 100 platforms.
Taxpayers who proactively reconstruct and file or amend prior years are in a materially different position than those who wait for IRS correspondence. Voluntary correction typically involves lower penalties, more available abatement options, and significantly less procedural complexity than responding to an examination after the fact.
A taxpayer who files a current year return with embedded prior year errors and is subsequently examined faces exactly that full history inquiry. For investors with multi-year activity that has never been reconciled, prior year correction is not optional, it is a prerequisite for current year accuracy.
What the Process Looks Like
In our experience at Camuso CPA, the majority of calculations we review from new clients, whether prepared by the taxpayer directly or by a firm, require full reconstruction from the earliest year of activity. Partial corrections that address only recent years rarely produce a defensible result because the errors inherited from earlier periods remain embedded in the inventory.
The practical starting point is the first year of activity where records are incomplete, where software defaults produced incorrect results, or where the return was not filed at all.
From that point, reconstruction works forward year by year, correcting the lot inventory and establishing a defensible ending position for each year before moving to the next. Where prior returns need to be amended, the amended returns are prepared from the corrected inventory. Where years were not filed, the returns are prepared from scratch using the reconstructed records.
Once the historical record is correct, current year reporting works from that foundation. The cumulative error is resolved, the inventory is defensible, and the current year return reflects actual positions rather than accumulated assumptions.
The timeline depends on the volume of activity, the number of platforms involved, and how complete the underlying records are. Engagements with limited platform history and accessible records move more quickly. Engagements spanning many years across multiple exchanges, self-custody wallets, and DeFi activity require more evidentiary work. A qualified crypto CPA can provide a realistic scope assessment once the full history is reviewed.
For investors whose prior year activity has never been fully reconciled, our crypto cost basis reconstruction services and crypto tax preparation services are built to address exactly this problem from the first year of activity through the current return. Work with a crypto CPA established in this market since 2016.
Contact us to discuss your situation
Frequently Asked Questions
Can I just start tracking my crypto correctly this year and ignore prior years?
Not without accepting significant compliance and audit risk. Prior year errors are embedded in the lot inventory the current year depends on. Starting fresh without correcting the underlying records means current year reporting is built on a defective foundation, and any IRS inquiry can reach back through the full history. With broker reporting now live and IRS matching systems ingesting that data, the prior year errors that were previously invisible are now surfacing as discrepancies on current year returns.
How far back do I need to go?
Reconstruction generally begins at the first year of digital asset activity, or at the first year where errors or gaps can be identified. A qualified crypto CPA can help assess which years are in scope based on the specific facts.
What if I can’t find records from prior years?
Missing records do not eliminate the obligation to substantiate basis, they change how the reconstruction is approached. When primary records are unavailable, reconstruction works through secondary sources such as bank records, email confirmations, platform support archives, and on-chain data. Where gaps remain after exhausting available sources, conservative assumptions are documented in a formal assumptions register. The reconstruction posture is designed to produce the most defensible position possible from whatever evidence exists.
Will I owe penalties for prior year errors?
Penalty exposure depends on the specific facts, including whether returns were filed, the nature of the errors, and whether the taxpayer acted in good faith. Proactive correction generally results in better outcomes than waiting for IRS correspondence. Penalty abatement options are more available in a voluntary correction context than in an examination context. A qualified crypto CPA can assess the specific exposure and available options before any corrected returns are filed.
What does the IRS actually look at in a crypto audit?
In active crypto examinations, the IRS has been issuing information document requests covering the taxpayer’s complete digital asset custody history across all exchanges, wallets, and self-custody addresses ever used. The scope routinely covers more than 100 platforms and reaches back to the beginning of the taxpayer’s activity. It is not limited to the year under examination. This is why prior year errors cannot be treated as resolved simply because time has passed or because a current year return was filed cleanly.
