A 2018-2022 crypto trader rebuilding incomplete books today is doing two things at once: reconstructing what should have been on the original return (basis, realization events, character) and assessing whether the penalties the IRS assessed against the original, late-filing penalties, failure-to-pay penalties, estimated-tax penalties, accumulated interest, were computed off the right baseline under the Kwong v. United States postponement reading of IRC § 7508A(d).
The first track is amendment work. The second track is a Form 843 protective claim under Treas. Reg. § 301.6402-2(b)(1), with the TAS-published deadline of July 10, 2026 as the hard external constraint. The companion piece (Crypto Amended Returns, Penalty Exposure, and Kwong) walks through the procedural framework. This piece focuses on the crypto amendment files where that overlap is easiest to miss.
Fact pattern 1, High-volume DeFi traders, 2020-2021
DeFi summer 2020 generated unprecedented daily transaction volume for active wallets. A single Uniswap V2 wallet running automated arbitrage in mid-2020 could generate hundreds to thousands of token-to-token swaps per month, each one a realization event under IRC § 1001 as applied to digital assets via Notice 2014-21 (Q&A 5-6) and confirmed by the Treas. Reg. § 1.1001-1 general realization-event framework. The standard fact pattern:
- Original 2020 return filed late (extension to October 15, 2021, then often slipping into 2022)
- Form 8949 line count in the hundreds to thousands
- Tax preparer relied on crypto-tax-software output that may have used a basis method (HIFO, FIFO, specific identification) inconsistent with the taxpayer’s chosen method
- Multiple wallets, multiple exchanges, multiple chains, some on-chain reconstruction from blockchain explorers, some from CSV exports that didn’t survive software-vendor migrations
- 2020 short-term capital gains likely realized at one mark-to-market level, but the underlying year ended with sharply reduced positions, generating a tax liability the taxpayer didn’t have liquid funds to pay
- IRS assessed § 6651(a)(2) failure-to-pay penalty (TC 276), § 6654 estimated-tax penalty (TC 170 or TC 176), and § 6601 interest (TC 196) against the original April 2021 payment deadline
For this fact pattern, all three IRS penalty assessments accrue from due dates inside the COVID postponement window through July 10, 2023. The 2020 calendar quarterly estimated-tax deadlines (April 15, June 15, September 15, 2020 and January 15, 2021) also sit inside the postponement window. All four sources of penalty exposure are in Kwong scope.
The amendment work, correcting the basis methodology, reconciling against exchange-provided figures (where available), adding any missed realization events, and adjusting the Schedule D / Form 8949 totals, proceeds on Form 1040-X with its own procedural calendar. The Kwong protective filing is a separate Form 843 packet that targets the penalties and interest the IRS already assessed against the original return. Both filings can move forward in parallel. See the Sheepdog Tax crypto amended return guide for the amendment-side mechanics.
Fact pattern 2, NFT bubble 2021, late-filed with character issues
NFT trading activity in 2021 generated complex character-and-timing questions that many tax preparers had not yet absorbed when 2021 returns were being filed in 2022-2023. The standard fact pattern:
- High-volume NFT mints and secondary sales in calendar 2021
- Gas fees paid in ETH, generating their own realization events at fluctuating ETH valuations
- Some NFTs held briefly (short-term capital under IRC § 1222(1)), some held longer (long-term capital under IRC § 1222(3), and for collectibles within the scope of Notice 2023-27 and IRC § 408(m)(3), potentially subject to the higher 28% rate under IRC § 1(h)(4))
- Original 2021 return either filed late or filed on time with material understatements that later required amendment
- IRS assessed § 6651(a)(1), § 6651(a)(2), and § 6601 amounts against the original April 2022 due date
- 2021 estimated-tax deadlines (April 15, June 15, September 15, 2021 and January 18, 2022) all sit inside the postponement window through July 10, 2023
Like the DeFi pattern, this fact pattern’s penalty exposure is concentrated in due dates inside the Kwong-recognized postponement window. The amendment work additionally raises character issues, what was reported as a capital gain may have been collectible-rate gain under § 408(m); what was reported as ordinary income from minting activity may have been capital gain on subsequent disposition. The amendment work and the protective claim are independent: the amendment corrects character; the protective claim challenges how the penalties on the original assessment were computed.
The amendment-and-protective parallel track is particularly valuable for NFT traders because the substantive recomputation under Kwong (penalties recomputed off the postponed due date rather than the original) and the amendment-side character corrections operate independently. A favorable result on either track does not require a favorable result on the other.
Fact pattern 3, Multi-wallet reconstruction, 2018-2022, pre-Rev. Proc. 2024-28
Many active traders during 2018-2022 used multiple wallets across multiple exchanges and chains. Pre-Rev. Proc. 2024-28, basis tracking under Treas. Reg. § 1.1012-1 was per-pool (or worse, per-platform), making cross-wallet reconciliation difficult. Exchange shutdowns, rebrand events, and software-vendor migrations frequently lost user-level basis history.
A taxpayer rebuilding 2018-2022 books today typically encounters:
- Incomplete CSV exports from now-defunct or rebranded exchanges
- Blockchain explorer reconstruction for on-chain activity, with gas costs and transaction fees in mixed denominations
- Cross-wallet transfers that look like disposals from the perspective of any single wallet’s basis tracker but are not disposals from the taxpayer’s perspective
- Software-vendor migration errors that double-counted or zero-counted specific events
- Pre-2025 basis tracking that was unavoidably per-pool / per-platform rather than per-wallet as Rev. Proc. 2024-28 now requires going forward
When the reconstruction work produces a corrected tax liability for any of 2018-2022, the amendment goes on Form 1040-X. If the original return for any of those years carried § 6651 / § 6654 / § 6601 assessments, and most 2018-2022 multi-wallet traders’ returns did, the Kwong protective claim is the parallel filing for the penalty side.
The reconstruction itself does not affect the Kwong scope. The protective claim challenges how the penalties on the original assessment were computed; it does not depend on whether the underlying tax liability later changes through amendment. The two filings remain separate.
Fact pattern 4, Late-extension stacks running into 2022-2023
A common 2018-2022 pattern: taxpayer filed Form 4868 for an extension to October 15 of the year following the tax year. Then October came, the reconstruction work wasn’t done, and the return was filed late, sometimes well into the following calendar year. Each successive extension-stack delay generated additional § 6651 and § 6601 accruals.
For tax year 2020 specifically: the original April 15, 2021 deadline; the extended October 15, 2021 deadline; the actual filing in (say) March 2022 or later. The penalty period accrues from the original April 15, 2021 deadline through the actual filing date. Under the Kwong reading, the entire postponement window through July 10, 2023 is in scope, so the full accrual period from April 15, 2021 through July 10, 2023 (or through the actual filing date if earlier) is the period for which Kwong says the penalties may have been computed off the wrong baseline.
This fact pattern produces the largest dollar exposures in typical 2018-2022 crypto trader files. The accrual period covers a multi-year stretch of penalty-and-interest compounding. The protective claim’s reservation-of-rights covers the entire period; the substantive recomputation later (after the IRS administratively responds to the protective claim or the contingency otherwise resolves) is where the dollar amount gets fixed.
A five-step review for crypto amendment files
For any 2018-2022 crypto-trader amendment engagement, the Kwong overlap can be tested with a five-step scan:
- Pull the IRS account transcript for each amendment year being considered (see STR Kwong III for the transcript-reading discipline).
- Identify the in-scope penalty entries, TC 166, 170, 176, 196, 276. For each, note the posting date and the original due date the assessment ties back to.
- Check for reversals, TC 167, 197, 277. Reversed amounts are out of scope.
- Confirm the due-date-inside-postponement test, does the assessment’s underlying due date fall inside the COVID postponement window through July 10, 2023?
- Flag the year for parallel filing, if any in-scope entries remain, the year is Kwong-eligible and a Form 843 protective filing should be drafted alongside the 1040-X amendment.
The check should be standard scoping discipline, not a separate engagement step. For an active 2018-2022 crypto-trader amendment file with late-filing or penalty exposure, the Kwong intersection recurs often enough to justify checking routinely, the fact patterns above are recurring, not theoretical.
What the protective claim does not change
A few clarifications on what the protective claim does not cover, specific to crypto-trader fact patterns.
It does not address character corrections. If the amendment work shifts gain from short-term to long-term, or from ordinary to capital, the Kwong protective claim is silent on that. Character corrections happen on the 1040-X. The protective claim targets only the penalties and interest as assessed against the original return.
It does not relieve the underlying tax. If the amendment work increases the underlying tax liability (e.g., catching previously omitted realization events), the additional tax is owed regardless of the Kwong protective filing. The protective claim targets the penalty and interest computation, not the underlying tax computation.
It does not address state-level penalties. State penalty assessments run on state procedural calendars that are unaffected by federal IRC § 7508A(d) postponement. A taxpayer with state-level penalty exposure has to evaluate that exposure separately, using whichever state-level relief mechanisms apply.
It does not address Form 8938 / FBAR exposure for offshore exchanges. If the 2018-2022 amendment work surfaces FinCEN Form 114 (FBAR) or Form 8938 (FATCA) reporting issues for offshore-exchange-held crypto, those have their own penalty regimes and their own procedural calendars. The Kwong protective claim targets domestic income-tax penalties; offshore-reporting penalties are a separate analysis.
When sequencing and documentation become material
This overlap between crypto amendment work and a Kwong protective filing becomes procedurally sensitive for three specific reasons:
The transcript triage requires fluency in IRS transaction codes. The five-code analysis from STR Kwong III is not what crypto-trader tax software typically surfaces. The transcript-reading discipline is a manual review function, not a software output.
The amendment-and-protective parallel track requires sequencing judgment. A taxpayer who amends and pays the additional tax before filing the protective claim may shift the recovery posture from refund (paid amounts) to abatement (unpaid amounts) for items that flip status during the process. The right sequencing depends on the taxpayer’s specific facts and the IRS-side processing posture.
The crypto reconstruction layered with the protective claim creates documentation-trail complexity. The 1040-X needs supporting documentation for the corrected basis, character, and realization-event totals. The protective claim needs supporting documentation for the in-scope penalty entries. Both filings need to reference each other where the substantive scope overlaps. If those two documentation tracks are prepared independently, timing and scope ambiguities are more likely.
For a 2018-2022 crypto trader already working through amendment scoping, see the Sheepdog Tax crypto amended return guide for the amendment-side framework, the Kwong overlap should be checked whenever the file includes late-filing, late-payment, or estimated-tax penalty exposure. The July 10, 2026 deadline matters because the protective-claim track runs on its own filing calendar.
Article authority anchors: Kwong v. United States, 179 Fed. Cl. 382 (Fed. Cl. 2025); IRC §§ 7508A(d), 1001, 6045, 6402, 6511, 6601, 6651, 6654, 7502; Treas. Reg. § 301.6402-2; Notice 2014-21; Notice 2023-27; Rev. Proc. 2024-28; IRC § 408(m); IRC § 1(h)(4); IRC § 4868 (extension); IRS account transcript transaction code definitions; Form 843, Form 1040-X, Form 8949 instructions; Form 8938 / FinCEN Form 114 reporting frameworks (referenced as separate-track exposure only); National Taxpayer Advocate blog Parts I and III.