ARK 21Shares Bitcoin ETF (ARKB) Review

TL;DR. ARK 21Shares Bitcoin ETF (ARKB) held $1.889 billion of net assets and 32,178.23 BTC at 30 June 2026 (Q2 2026 10-Q), which makes it the sixth-largest US spot Bitcoin ETF, behind IBIT, FBTC, GBTC, the Grayscale Mini and BITB. The fee is 0.21% and the bitcoin is spread across four custodians. The branding is misleading in one important way: the sponsor is 21Shares US LLC, a wholly owned subsidiary of 21co Holdings Limited whose ultimate parent is FalconX Holdings Limited. ARK Investment Management LLC is the fund's sub-adviser and helps market the shares — it does not run the trust.

The basics

Who actually runs ARKB

The ticker and the marketing put ARK first, but the filings do not. Per the Q2 2026 10-Q:

• 21Shares US LLC is the sponsor — the entity that manages and controls the trust. It was formed in Delaware on 16 June 2021 and is a wholly owned subsidiary of 21co Holdings Limited; the ultimate parent is FalconX Holdings Limited.
• ARK Investment Management LLC is the sub-adviser and "provides assistance in the marketing of the Shares." It is not the sponsor, and the shares are neither interests in nor obligations of it.
• CSC Delaware Trust Company is the trustee; The Bank of New York Mellon is administrator, transfer agent and cash custodian.

If you bought ARKB because you wanted a Cathie Wood product, understand what you own: a passive bitcoin trust run by 21Shares' US arm, now sitting under FalconX, with ARK in a marketing and advisory seat.

Fees

ARKB launched with the sponsor fee waived entirely for either a nine-month period from the 11 January 2024 listing or the first $1 billion of trust assets, whichever came first. Trust assets passed $1 billion in February 2024, which is when the waiver ended — well before the nine-month clock ran out. The fund has charged the full 0.21% since. That is slightly below IBIT and FBTC at 0.25%, and above Franklin EZBC (0.19%), the Grayscale Mini (0.15%) and Morgan Stanley MSBT (0.14%).

The 4 bp fee advantage vs IBIT is real but small. On a $100k position over 10 years: ARKB saves $400 vs IBIT. Worth optimising if you have multiple options and no other preference; not worth optimising if other factors (broker availability, liquidity) point elsewhere.

Full fee comparison: Bitcoin ETF expense ratios compared.

Tracking quality

21Shares publishes the figures, which puts ARKB ahead of Fidelity on disclosure if not on size. At 23 September 2026 the fund page showed a 30-day median bid-ask spread of 0.04%, $2.88 billion of assets under management and daily volume of 1.87 million shares.

Issuer fund pages, 23 September 2026.

0.04% is genuinely wider than IBIT's 0.02% on the same date, and — the detail that undercuts the usual size-ranks-everything story — wider than Bitwise BITB's 0.0234%, even though ARKB trades about twice BITB's daily share volume. On a $10,000 purchase the round-trip difference against IBIT is roughly $4. On a $10 million block it is about $4,000, which is the order size where it starts to matter.

21Shares also discloses premium and discount the way issuers actually measure it — extremes and day counts, not a tidy average. Over the period shown, ARKB's greatest premium was +0.41% (3 September 2026) and its greatest discount −0.71% (29 July 2026), with 33 days at a premium, 20 at a discount and 5 at NAV. Those swings are an order of magnitude larger than the spread, and they are why a limit order beats a market order here.

The benchmark change: CME CF out, FTSE in

One structural change happened in 2026 that most ARKB write-ups have not caught up with. On 30 June 2026 the sponsor gave CF Benchmarks notice that it was terminating the licence for the CME CF Bitcoin Reference Rate — New York Variant, effective 31 August 2026 (8-K filed 7 July 2026). On 20 August 2026 it signed a licensing agreement with FTSE International Limited, and from 27 August 2026 the trust values its shares and calculates NAV by reference to the FTSE Bitcoin Index instead (8-K filed 26 August 2026).

In practice the two indices track the same asset and the difference in daily NAV should be immaterial. It matters for anyone reconciling ARKB's NAV against a CME CF-based price series: after 27 August 2026 you are comparing against the wrong reference rate.

The brand factor

ARK Invest's brand cuts both ways for prospective ARKB holders:

• Positive: high name recognition with retail advisors and US growth-equity allocators. Cathie Wood's media presence drives organic awareness.
• Negative: ARK's broader equity ETFs underperformed during 2022–2023, and the firm carries some reputational baggage among institutional allocators. ARKB itself is a passive bitcoin product unrelated to ARK's stock-picking record, but the association affects perception.

For pure bitcoin exposure the ARK brand is essentially irrelevant — the product is a passive trust. For investors who specifically want or specifically avoid ARK as a fund family, it matters.

Custody

ARKB no longer sits on a single custodian. The Q2 2026 10-Q names four: Coinbase Custody Trust Company, BitGo Bank & Trust, N.A., BitGo New York Trust Company, LLC and Anchorage Digital Bank N.A. The filing does not break out how much bitcoin sits at each, so this is diversification of legal entities rather than a published split — but it is more than the single-custodian arrangement most of the category still runs, and more than IBIT's (Coinbase, with Anchorage named but unused).

Coinbase is still in the list, so ARKB does not remove Coinbase exposure. The only large fund that does is Fidelity FBTC.

The case for ARKB

• Below-IBIT fee. 0.21% beats IBIT and FBTC by 4 bp.
• Four custodians. More spread across custody entities than any other large fund in the category.
• Published metrics. 21Shares discloses median spread and premium/discount extremes; Fidelity, the second-largest issuer in the category, discloses neither.
• Non-BlackRock alternative. If you want category diversification away from IBIT, ARKB is the most credible second pick.

The case against ARKB

• Not the cheapest. EZBC (0.19%), the Grayscale Mini (0.15%) and MSBT (0.14%) are all lower.
• Coinbase is still in the mix. Four custodians, but Coinbase is one of them — this is not a way to avoid Coinbase.
• Much smaller than IBIT/FBTC. $1.89bn against IBIT's $43.39bn at 30 June 2026; wider spreads for institutional block trades.
• The brand is not the manager. ARK's name is on the fund, but 21Shares US LLC runs it under FalconX ownership.

Who should consider ARKB

Sensible default for:

• Investors who already use ARK funds and want to consolidate at one fund family.
• Allocators looking for a non-IBIT, non-Grayscale option at a competitive fee.
• Anyone splitting bitcoin exposure across two issuers for risk diversification.

Probably not the right choice if:

• You're fee-optimising to the bottom — MSBT (0.14%), the Grayscale Mini (0.15%) and EZBC (0.19%) are all cheaper.
• You need maximum liquidity for large orders — go to IBIT.
• You want no Coinbase exposure at all — that is FBTC, not ARKB.

FAQ

Sources and further reading

• ARK 21Shares Bitcoin ETF Form 10-Q for the quarter ended 30 June 2026 — sec.gov/Archives/edgar (CIK 0001869699).
• Forms 8-K of 7 July 2026 (CF Benchmarks licence termination) and 26 August 2026 (FTSE Bitcoin Index licence) — sec.gov.
• Internal: Bitwise BITB review, BlackRock IBIT review, Expense ratios compared.