You filed the extension. Good. April 15 came and went, Form 4868 was submitted, and you have until October 15 to get your 2025 return filed. That’s the move for a lot of crypto traders — and it’s a completely legitimate one.
But here’s where people go sideways: they file the extension, exhale, and then do nothing for four months. Then October 10 rolls around and they’re staring at a stack of 1099-DAs, a multi-chain wallet history, and the slowly dawning realization that these six extra months were not actually six months of free time.
Let’s talk about what’s actually on your plate — and what the 1099-DA situation means for people using the extension window.
The Extension Buys You Time to File. Not Time to Pay.
This is the one that trips people up every year.
Taxpayers can apply for a six-month extension to file their tax returns using IRS Form 4868. While the extension grants more time to file, it does not extend the time to pay any taxes due — which means estimated taxes must be paid by the original due date to avoid penalties.
If you owed tax for 2025 and didn’t send a payment by April 15, interest has been running since then. The extension didn’t pause that clock. It only paused the late-filing penalty. Two different things.
If you significantly underestimated what you owed — say, you had a big Q4 2025 run and forgot about it — the gap between what you paid in April and what you actually owe is accruing interest right now. Worth checking before October.
What 1099-DA Actually Covers (And What It Doesn’t)
This is the first real tax season where 1099-DA is live. The introduction of Form 1099-DA represents the most significant change to crypto tax reporting since the IRS first classified digital assets as property. Starting with the 2025 tax year (2026 reporting year), this form is fundamentally changing how crypto transactions are reported and tracked.
The short version: your Coinbase, Kraken, and other major centralized exchanges sent a 1099-DA to you and to the IRS reporting your gross proceeds from 2025 sales. The IRS has both copies. They will match them.
For 2025 transactions, custodial brokers are required to report gross proceeds only. Cost basis reporting is not required for 2025 transactions, though some brokers may report it voluntarily.
That’s the first problem. Your 1099-DA likely shows a large gross proceeds number with no cost basis attached — or a $0 basis if you transferred in from another wallet or exchange. If you transferred Bitcoin from a hardware wallet to an exchange and sold it, the exchange may report a $0 cost basis to the IRS.
The second problem: the IRS receives a copy of every 1099-DA issued to you. If your tax return does not perfectly match the gross proceeds reported on these forms, it triggers an automated red flag, potentially leading to a CP2000 notice or a full IRS audit.
Using the extension window to reconcile your 1099-DAs against your actual transaction records isn’t optional. It’s the whole job.
The Basis Gap Is Your Problem to Solve
Accountants should expect reconciliation gaps and should not assume that proceeds on the 1099-DA match the client’s actual taxable gain. Taxpayers remain responsible for tracking their own cost basis regardless of what the broker reports.
This matters most if you:
- Moved assets between exchanges. The receiving exchange doesn’t know what you paid. Neither does the 1099-DA.
- Self-custodied at any point. Hardware wallet → exchange → sale means the exchange reports proceeds, not gains. Your basis is invisible to them.
- Traded across chains. DeFi activity, NFT sales, and wallet-to-wallet transfers won’t appear on a 1099-DA. Certain DeFi activities are not yet subject to broker reporting under current IRS rules, but may still be taxable. You’ll need to track and report these yourself.
- Farmed, staked, or earned yield rewards. None of that income appears on 1099-DA either. It still has to go on your return.
In the first year of reporting, brokers generally report gross proceeds while cost basis may be missing — especially when assets move between wallets, exchanges, chains, or DeFi environments outside broker visibility. You should not prepare your tax return from the 1099-DA alone. Reconcile the form to your wallet and exchange records, document your cost basis and accounting method, and retain support in anticipation of IRS matching and automated notices.
The 1099-DA is not your return. It’s one imperfect data source that needs to be reconciled against everything else you have.
What the October 15 Deadline Actually Requires
October 15 is the last possible day to file your 2025 return if you filed Form 4868 in April. No further extensions are available.
There is no Form 4868 Part Two. No emergency extension. Late filing increases audit risk, especially for crypto investors. The IRS specifically targets cryptocurrency transactions, and late filing raises red flags.
For 2025 returns, your complete filing needs:
- Form 8949 — every disposal, short-term and long-term, reconciled against your 1099-DAs
- Schedule D — capital gain/loss summary
- Schedule 1 (or Schedule C) — ordinary income from staking, mining, airdrops, and yield rewards
- FBAR / Form 8938 — if you had foreign exchange exposure that meets the threshold
If your 1099-DA gross proceeds don’t match your Form 8949 entries exactly, that mismatch needs an explanation. The IRS doesn’t like unexplained gaps. Providing one proactively is far better than receiving a CP2000 in eighteen months.
Wallet-by-Wallet Accounting Is Now the Rule
Starting January 1, 2025, the IRS moved to wallet-level basis tracking. The rules for determining cost basis have changed. Crypto investors must transition from universal accounting to wallet-by-wallet accounting. For digital assets acquired before January 1, 2025, taxpayers must rely on their previous tax reports and the safe harbor guidance provided in Revenue Procedure 2024-28.
If you’re still using a blended cost basis across all wallets and exchanges, that approach is no longer compliant with the current framework. Your October deadline is a good forcing function to get this right before it’s an audit issue.
What to Do With the Time You Have Left
You have until October 15. That’s roughly five and a half months from now. Here’s how not to waste it:
- Pull every 1099-DA you received. Cross-reference them with your own transaction records. Note every discrepancy.
- Export transaction histories from every exchange and wallet. The older the exchange, the worse the export quality. Do it now before CSV formats change or accounts get restricted.
- Identify your DeFi and on-chain activity. Swaps, LP entries and exits, staking rewards, bridge transactions — none of this appears on a 1099-DA, all of it may be taxable.
- Document your cost basis methodology. FIFO, Specific ID — know which you’re using, apply it consistently per wallet, and be able to defend it.
- Estimate whether you underpaid in April. If you owe significantly more than you paid, the interest clock is already running.
Extension season is not a vacation. It’s a preparation window. The difference between a clean October filing and a panicked October call to a preparer is almost always whether someone started pulling records in May or waited until September 30.
This isn’t tax advice — your specific situation may differ significantly from the general guidance here, and you should consult a qualified tax professional before filing. If you have a complex 2025 return — multi-chain activity, 1099-DA mismatches, DeFi income, or missing basis — reach out to us. That’s exactly what we’re here for.
