The IRS's new digital asset reporting form is no longer theoretical. Brokers filed the first-ever Form 1099-DA for the 2025 tax year. Self-custody holders, early Bitcoin buyers, and families planning generational transfers face a cost basis documentation crisis — and most have no idea it's coming.
Tax season 2026 marks a turning point in Bitcoin's relationship with the IRS. For the first time, US brokers — centralized exchanges like Coinbase, Kraken, and Fidelity Digital Assets — are filing Form 1099-DA reports with the IRS, covering digital asset sales made in the 2025 tax year. By 2026 transactions, the reporting expands further to include cost basis for "covered" digital assets.
If you hold Bitcoin on a centralized exchange, you are already inside this reporting regime. If you hold Bitcoin in self-custody — hardware wallets, cold storage, multi-sig — you are outside it, and that creates a different but equally serious problem: the IRS will eventually expect you to prove your basis with no broker to back you up.
For Bitcoin families with multigenerational wealth objectives, Form 1099-DA isn't just a tax compliance issue. It's an estate planning crisis in slow motion. The documentation gaps being created today — in how families hold, transfer, and plan around their Bitcoin — will determine whether heirs receive the full value of their inheritance or hand a substantial portion of it to the IRS.
This article explains how Form 1099-DA works, where it breaks down for estate planning purposes, and exactly what Bitcoin families need to do now to protect their wealth across generations.
Form 1099-DA cost basis reporting begins for 2026 transactions. If your estate plan involves transferring Bitcoin into trusts, LLCs, or to heirs, the basis documentation decisions you make right now will determine your family's tax liability for decades. This is not a future problem — it is a current one.
Form 1099-DA — Digital Asset Proceeds from Broker Transactions — is the IRS's answer to a decade of underreporting in the cryptocurrency market. Under Treasury Department final regulations issued in 2024 (TD 10000, 26 CFR Parts 1, 31, and 301), brokers engaging in digital asset transactions are now subject to the same information reporting requirements that have long applied to stock brokers and mutual fund companies.
The rollout is phased:
Here's the reality for most serious Bitcoin holders: if you bought Bitcoin at any point before 2026 — especially if you've moved it between wallets, exchanges, or cold storage — your cost basis is almost certainly classified as "noncovered." Your broker will report your proceeds when you sell, but will have little or no cost basis data to match against it.
The IRS's default assumption when it receives a 1099-DA showing proceeds but no basis? Your cost basis was zero. That means the entire sale amount is potentially treated as taxable gain.
For a family that bought 10 Bitcoin at $5,000 in 2020 (total cost: $50,000) and sells at $71,000 each (total proceeds: $710,000), the actual taxable gain should be $660,000. Without documented basis, the IRS could treat the entire $710,000 as gain — creating a $213,000+ additional tax liability at the 30% effective rate that vanishes the moment you can produce your original purchase records.
If your Bitcoin lives in hardware wallets (Coldcard, Ledger, Trezor, Passport, Keystone), multi-sig setups, or any form of cold storage: no broker will ever file a 1099-DA for those holdings. This protects your privacy — but it means the IRS has no independent record of your cost basis. Your estate's ability to prove the basis falls entirely on your own documentation.
Tax journalists and accounting blogs are covering Form 1099-DA from an annual compliance angle: how do you file your 2025 return correctly? What software handles 1099-DA data? How do you reconcile the form against your own records?
That's the wrong frame for Bitcoin families. The real question is: what happens to your cost basis documentation when you die?
Under current US tax law (IRC §1014), assets included in a decedent's gross estate receive a "stepped-up basis" — meaning heirs inherit the asset at its fair market value on the date of death, not the original purchase price. The unrealized capital gain accumulated during the decedent's lifetime is permanently eliminated.
For Bitcoin holders, this is the single most powerful tax benefit in the entire estate planning toolkit:
Original purchase: 5 BTC at $10,000 = $50,000 basis
Sale at $71,000 each = $355,000 proceeds
Long-term capital gains tax (23.8% with NIIT): ~$72,590 owed
Original purchase: 5 BTC at $10,000 = $50,000 original basis
Value at death: $71,000 each = $355,000
Heirs inherit at $71,000 basis. Entire $305,000 gain is permanently eliminated
This makes the decision about when to sell Bitcoin a fundamentally different calculation than most people realize. Families with appreciated Bitcoin positions that they don't need for liquidity during their lifetime should seriously consider whether passing Bitcoin directly to heirs — with proper custody and inheritance planning — is more tax-efficient than selling during life.
Here's where 1099-DA creates a new wrinkle for estate planning. When Bitcoin is held in a custodial account at death, the broker will have basis records — but those records may be incomplete, incorrect, or show "noncovered" status for older positions. The executor of the estate, and ultimately the heirs, must be able to prove:
If the estate's records are poor — if the decedent bought Bitcoin across multiple exchanges, some of which no longer exist, moved it into cold storage, transferred it to a hardware wallet with no documentation — the executor faces a nightmare reconstruction project at exactly the moment when they can least afford it.
Bitcoin transfers into irrevocable trusts, grantor trusts, LLCs, or family partnerships for estate planning purposes are treated as transfers from an "unhosted" wallet to a new custodial entity. Under 1099-DA rules, assets that arrive at a broker via transfer from an outside wallet are classified as noncovered securities — the broker has no basis history for them.
This means: if you transfer Bitcoin into an irrevocable trust for estate planning purposes, and that trust later sells or distributes the Bitcoin, the trust's basis documentation is entirely self-maintained. The trust document, combined with records proving the original acquisition cost, becomes the sole source of truth for tax purposes.
Your estate planning attorney should be documenting this explicitly in the trust's records — and your trustee should be maintaining a formal basis ledger for all digital assets held in the trust.
Before the IRS starts matching 1099-DA proceeds against your returns with no basis, build your own complete basis file. Pull transaction histories from every exchange you've ever used. If exchanges have closed, check email confirmations, bank statements, and blockchain transaction records. For self-custody holdings, your wallet's transaction history can be matched against price data to reconstruct cost basis with reasonable accuracy. Software like Koinly, Cointracker, or TaxBit can automate much of this reconstruction.
Under IRS Rev. Proc. 2024-28, taxpayers using centralized exchanges must choose a cost basis accounting method — FIFO (first in, first out), HIFO (highest in, first out), or specific identification — and document it per wallet. For estate planning purposes, specific identification often produces the best outcome because it lets you choose which lots to sell (preserving low-basis lots for the stepped-up basis at death). Your choice must be made before your first 2025 sale, and must be documented with your records.
Create a formal Bitcoin inventory for estate planning purposes: wallet addresses, exchange accounts, ETF positions, multi-sig keyholders, and any hardware wallet locations. This document — sometimes called a "digital asset letter of instruction" — is separate from your will and trust (which are public documents that should not contain private keys). Store it with your attorney or in a fireproof safe accessible to your executor or successor trustee.
If you have an existing irrevocable trust, dynasty trust, or family LLC holding Bitcoin, ask your estate attorney to review whether the trust document addresses the trustee's obligation to maintain digital asset basis records. Trusts drafted before 2025 almost certainly don't address 1099-DA. A trust amendment or restatement can add explicit provisions — or at minimum, the trustee should adopt a formal digital asset accounting policy now.
For any Bitcoin position where you are sitting on significant unrealized gains, model the stepped-up basis scenario explicitly. If your estate is below the federal exemption threshold ($15M per individual in 2026), passing Bitcoin to heirs with the full step-up may eliminate far more tax than any income tax planning strategy during your lifetime. If your estate is above the exemption, the estate tax math changes — but the capital gains step-up still applies to whatever passes to heirs, making the planning more layered.
The 2025 Form 1099-DA reports gross proceeds — meaning the IRS sees your Bitcoin sales even if cost basis isn't on the form. If your 2025 return doesn't correctly reconcile the 1099-DA proceeds against your documented gains and losses, you'll receive an IRS notice (typically CP2000) asserting you underreported income. Have your tax preparer access your complete transaction history, not just the 1099-DA, and reconcile the full picture. For complex multi-exchange, multi-wallet situations, a crypto-specialized CPA is worth the cost.
The best estate plan is one where your executor or successor trustee doesn't have to solve a custody crisis while grieving. For Bitcoin intended to pass to the next generation, the right custody architecture is designed for institutional continuity — not just individual convenience. Multi-sig with a professional keyholder (Unchained, Casa, or a qualified custodian at higher amounts) ensures continuity of access even if you are incapacitated or deceased, with no single point of failure.
For families that produce Bitcoin through mining operations, the basis calculation is different — and often dramatically more favorable for estate planning purposes. Mined Bitcoin has a cost basis equal to its fair market value at the time it is received (since it's treated as ordinary income). But the costs of mining — electricity, hardware, facilities, depreciation on equipment — are deductible against that income.
The result: Bitcoin mining families often have a higher cost basis on their mined Bitcoin than market buyers do, because the hardware and operational costs are deductible. This reduces the unrealized capital gain that needs stepped-up basis treatment at death — and creates a powerful tax deduction stream during life.
Mining is one of the most powerful tax strategies available for Bitcoin-wealthy families. Depreciation deductions, bonus depreciation, and OpEx treatment can dramatically reduce the effective tax burden while simultaneously building a larger Bitcoin position. For a complete breakdown: Bitcoin Mining as a Tax Strategy — Abundant Mines
Understanding the information asymmetry between you and the IRS is essential for 1099-DA planning:
What the IRS knows (from 1099-DA):
What the IRS does NOT know:
This asymmetry creates both risk and opportunity. The risk: if you can't prove your basis, the IRS defaults to zero. The opportunity: for self-custody holders with good documentation, you control the narrative — but only if that documentation survives you and is accessible to your estate.
None of the above analysis operates in isolation from your broader estate plan. Form 1099-DA creates documentation obligations that need to be integrated into three key planning documents:
Your will or revocable living trust should direct the executor/trustee to a separate "digital asset letter of instruction" (never include private keys in a will — it becomes a public document on probate). The letter should specify the location of every Bitcoin holding, the exchange accounts, any multi-sig keyholders, and where the basis documentation is stored.
If Bitcoin transfers to an irrevocable trust during your lifetime, the trust should specify: how digital assets are to be held (self-custody vs. custodian), who is authorized to manage them, how basis is tracked, and what happens to the Bitcoin on distribution to beneficiaries (a distribution of Bitcoin to a beneficiary is itself potentially a taxable event for the trust — the trustee needs to know the basis).
Your POA should explicitly authorize your agent to manage digital assets, access exchange accounts, transfer Bitcoin, and make cost basis method elections on your behalf if you become incapacitated. Many standard POA forms drafted before 2020 don't include digital asset authority — check yours.
The families that document their Bitcoin basis today won't be scrambling when the IRS comes calling — or when the next generation inherits. Join the waitlist for personalized guidance on digital asset estate planning, basis documentation strategy, and custody architecture.
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