IBIT vs FBTC vs the field: which spot Bitcoin ETF, and why it probably doesn't matter.
Eleven spot Bitcoin ETFs launched in January 2024. The two largest by AUM are IBIT (BlackRock) and FBTC (Fidelity). The differences between them are smaller than the marketing implies. The bigger decision is whether to hold any spot Bitcoin ETF at all versus self-custody.
This page covers product comparison. The framing assumes you've already decided to take a Bitcoin position; whether ETF or self-custody is the right wrapper depends on your situation.
Both IBIT and FBTC are spot Bitcoin ETFs that hold actual Bitcoin in custody. Both are below 0.30% expense ratioexpense ratioThe yearly fee an investment fund charges, taken as a small slice of your balance. A 0.03% ratio costs $3 per year on every $10,000 invested. Lower is better.Full definition. Both have over $20 billion in AUM. The differences (custodian, fee schedule, tracking error) are small enough that picking one over the other rarely changes long-run returns by a meaningful amount. The bigger choice is ETF vs self-custody, which is a different decision and is covered separately.
Side by side
- IBIT (iShares Bitcoin Trust) · sponsor: BlackRock · expense ratio 0.25% · AUM ~$60B+ · custodian: Coinbase Custody Trust
- FBTC (Fidelity Wise Origin Bitcoin Fund) · sponsor: Fidelity · expense ratio 0.25% · AUM ~$25B+ · custodian: Fidelity Digital Assets (self-custodied within the Fidelity ecosystem)
- ARKB (ARK 21Shares) · sponsor: ARK Invest + 21Shares · expense ratio 0.21% · AUM ~$5B · custodian: Coinbase Custody Trust
- BITB (Bitwise) · sponsor: Bitwise · expense ratio 0.20% · AUM ~$3-5B · custodian: Coinbase Custody Trust · 10% of profits to open-source Bitcoin development
- HODL (VanEck) · sponsor: VanEck · expense ratio 0.20% · AUM smaller · custodian: Gemini Trust
- GBTC (Grayscale) · sponsor: Grayscale · expense ratio 1.50% · AUM ~$15B · custodian: Coinbase Custody Trust · legacy fund; expense ratio is materially higher than peers
Verify current expense ratios and AUM from each sponsor's website before relying on these figures. They can change.
What actually differentiates them
Expense ratio
IBIT and FBTC both at 0.25%. ARKB at 0.21%, BITB at 0.20%. On a $100,000 position over 10 years, the difference between 0.20% and 0.25% is approximately $750 in fees (assuming flat price). Real, but not large.
Custodian
FBTC custodies internally at Fidelity Digital Assets. The other major issuers use Coinbase Custody Trust. Custodian concentration is a real systemic risk if Coinbase Custody were to fail. FBTC's in-house custody is a meaningful structural difference for risk-aware buyers.
AUM and tracking
Larger AUM means tighter bid-ask spreads and smaller premium/discount to NAV. IBIT is the largest by a wide margin. FBTC and ARKB are also large enough that retail orders execute essentially at NAV.
In-kind redemption status
As of 2026, US spot Bitcoin ETFs use cash creation/redemption rather than in-kind. This is a regulatory artifact (the SEC required cash-only at launch). The structural impact: marginal tax inefficiency for ETF sponsors (small) and slightly wider bid-ask spreads at the AP level. Not a meaningful retail concern.
When does the ETF wrapper actually make sense?
- Tax-advantaged accounts: if you want Bitcoin in a 401(k) brokerage window or a Roth IRAIndividual Retirement Account (IRA)A personal retirement savings account with tax advantages. Two main types: Traditional (tax now, pay later) and Roth (pay now, tax-free forever).Full definition, the ETF is the only practical option for most people. Self-custody inside an IRA requires a specialized custodian (Unchained, BitGo, etc.) and is more friction.
- Small allocations: for $1,000-$10,000 positions, the operational cost of self-custody (hardware wallet, seed-phrase management) is high relative to the position. ETF is fine.
- Heirs and estate planningestate planningOrganizing your assets and legal documents so they transfer correctly and efficiently when you die.Full definition: ETFs go through standard brokerage probateprobateThe court-supervised process of validating a will, paying debts, and distributing assets after death. Slow, costly, and public.Full definition channels. Self-custody requires careful seed-phrase inheritance planning.
- Trading flexibility: ETFs settle T+1 in your existing brokerage. Self-custody settles in 10 minutes but requires you to manage a wallet.
When self-custody wins:
- Large positions ($50K+)
- Long holding periods (10+ years)
- Concerns about counterparty risk
- Bitcoin philosophical alignment (your keys, your coins)
See ETF vs self-custody for the full framework.
If you have to pick one
Among IBIT, FBTC, ARKB, and BITB, the differences are small. The defaults at 2026 prices:
- Holding inside a Fidelity account: FBTC. Same custodian, no friction.
- Holding outside Fidelity, want maximum AUM and liquidityliquidityHow quickly and easily you can convert an asset to cash without significantly affecting its price.Full definition: IBIT.
- Holding outside Fidelity, want lowest fee: BITB at 0.20%.
- Avoid GBTC. The 1.50% expense ratio compounds to a meaningful drag over a long hold; cheaper alternatives are available with the same exposure.
Common questions
Do spot Bitcoin ETFs actually hold Bitcoin?
Yes. Each share represents a fractional claim on actual Bitcoin held in custody. The ETF custodian publishes daily holdings. This is structurally different from futures-based crypto ETFs (BITO, etc.) which hold derivatives and have meaningful tracking error.
What's the tax difference vs self-custody?
ETFs are securities subject to the wash sale rulewash sale ruleAn IRS rule preventing you from claiming a tax loss if you repurchase the same security within 30 days. Currently does not apply to Bitcoin.Full definition. Self-custody Bitcoin is property and not subject to the wash sale rule (as of 2026). For tax-loss harvestingtax-loss harvestingSelling an investment that has declined to realize a tax loss, then buying a similar investment, reducing your tax bill without changing your portfolio.Full definition, self-custody has the advantage. See Bitcoin wash sale.
Can I switch from IBIT to FBTC without tax consequences?
No. Both are securities. Selling IBIT to buy FBTC realizes gain or loss. Some brokers offer "cost basiscost basisWhat you originally paid for an asset. Used to calculate how much profit (or loss) you made when you sell.Full definition transfers" that move the position without selling, but only within the same fund. Cross-issuer moves require a sale.
Do these ETFs distribute capital gains?
Spot Bitcoin ETFs structured as grantor trusts (which most are) generally do not distribute capital gainscapital gainsThe profit from selling an asset for more than you paid for it. Taxed differently depending on how long you held the asset.. Investors only realize tax events when they sell their own ETF shares. Confirm the structure of any specific ETF before relying on this.
Should I hold an ETF and self-custody at the same time?
For many people, yes. ETF in tax-advantaged accounts (Roth IRA, brokerage window inside 401k) plus a self-custody position in taxable for the long-term hold is a common split. The ETF gets the tax shelter, the self-custody gets the sovereignty and tax-loss harvesting flexibility.
Related reading
- Spot Bitcoin ETF guide · the broader landscape
- ETF vs self-custody
- Bitcoin in a 401(k) · the brokerage-window play
- Bitcoin allocation
Last updated 2026-05-06. Not financial advice. Do your own research.
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