WBTC vs cbBTC: cbBTC added 42k BTC in a year while most others shrank

The first question is how much of cbBTC's growth came from other wrappers. Their combined decline makes substitution a plausible explanation, but measuring its size requires more than the supply lines.

BTCB contributes a large, flat part of the chart. Binance's wrapper on BNB Chain shows 65,301 BTC on every day of the two-year series. That matches the total supply reported by CoinGecko on 17 September 2026. The chart measures outstanding supply; a flat line does not establish that no minting and burning occurred between observations.

WBTC since the custody change#

The chart opens on 13 September 2024, the day after cbBTC went live. WBTC supply was 143k BTC that day and 109k two years later, a fall of 23%; 7k of that came in the trailing year.

When The Block reported cbBTC passing 30,000 tokens in August 2025, it attributed much of the growth to "substitution and migrational flows away from wBTC", helped by Coinbase converting customer withdrawals to cbBTC one for one.

The supply series cannot quantify that substitution. Other wrappers lost a net 13k BTC while cbBTC gained 42k, but new issuance elsewhere could have offset redemptions that moved to cbBTC. The 13k therefore places no upper bound on migration. The remaining 29k is growth in measured outstanding supply, not an identified inflow of previously unwrapped Bitcoin. Establishing where cbBTC's growth came from needs evidence connecting redemptions, Bitcoin transfers and subsequent mints.

Which months carried it#

Net minting by month is lumpier than the supply lines suggest. cbBTC netted +10k BTC in October 2025 and -11k in April 2026, its only large net-redemption month, then returned to net minting from May onward. WBTC's monthly net redemptions in the trailing year stayed under 2.5k BTC except in February 2026; the large WBTC net redemptions sit in the last quarter of 2024, right after the custody change, as the flows chart shows. LBTC and tBTC were net redeemed in most months of the year, never by more than 1k BTC in a month.

What each token is a claim on#

The larger cbBTC share changes which custody arrangement accounts for the tokens in this series. The relevant differences are who can redeem and who controls the underlying Bitcoin.

WBTC is minted and redeemed only by approved merchants, with the Bitcoin held in custody. On 9 August 2024 BitGo announced it would move that custody into a joint venture with BiT Global, a Hong Kong platform associated with Justin Sun. Five days later, BitGo revised the key arrangement so that one key each sits with BitGo in the United States, BiT Global in Hong Kong and BitGo Singapore.

cbBTC is backed one for one by Bitcoin held in Coinbase custody and has a single redemption path: a Coinbase customer deposits cbBTC to their account and receives BTC (Coinbase, pages as of 17 September 2026).

The smaller wrappers introduce other arrangements. tBTC uses threshold cryptography and a set of operators to control the Bitcoin. LBTC combines custody with a yield strategy: Lombard announced in August 2026 that its yield source would move from staking to a covered-call strategy run by Bitwise. These differences matter to a comparison of the claims, even when all are expressed in BTC units.

The measured shift is toward cbBTC's Coinbase custody arrangement. It does not establish that holders selected cbBTC for its custody model: distribution, borrowing access and redemption convenience can also affect which wrapper they hold.

What issuance data leaves out#

Monthly flows are netted per issuer. A month with equal minting and burning reads as zero, and a redemption does not identify its destination. The series also opens a month after BitGo announced the custody change, so it cannot establish whether the WBTC decline had already begun.

Where outstanding tokens sit is examined in the holder-type article. Issuance alone cannot show whether the larger cbBTC balance is held in wallets, supplied to lending markets or used elsewhere.