Start with who supervises the firm
Each exchange in this group publishes at least one register entry, and each entry pairs a supervisor with an identifier. That pairing is the first thing to set beside a fee or a headline bonus, because a competitive price only matters if you know which body would take a complaint. The identifiers are short strings rather than marketing language, and each can be looked up in the register of the body it names.
The spread is wide. bitbuy sits on a Canadian register under 160292, bit2c is listed with the Israeli securities authority under 72080, and bitcoin.de is registered with BaFin, the German financial supervision authority, under 118938. Where a broker or a plain crypto venue is the thing you actually want, the Ajaib review sets out how a different kind of account is built and what to ask about custody.
One identifier can cover more than one activity
bitbank shows why the label matters more than the presence of a number. Its entry with the Kanto Local Finance Bureau is for a registered crypto-asset exchange service provider, No. 00004. Its second entry is a different activity under a different authority: registration as a money lender with the Tokyo Metropolitan Governor, Tokyo Governor (2) No. 31821. An exchange permission and a lending permission are not interchangeable, so check what sits beside the identifier rather than whether one exists.
bitnovo shows the wider version of the same point, with entries in three European registers: D687 for Spain, E2023-102 for France and R193399 for the Netherlands. The Anycoin Direct review is a useful counterweight, since that firm lists a single Dutch entry, 41000015. One entry can be entirely adequate, but you should know that it is one entry.
What a European registration looks like
Several of these firms appear as crypto-asset service provider entries under the same European regime, drawn from a common supervisory register. Backpack is listed as MiCA CASP 6488C2PNI17093U2YA18, Banxa as MiCA CASP 69940000HAL9ODW3IMO22, bit.plus as MiCA CASP 315700I7V6W7BLAI9Z32, Bit2Me as MiCA CASP 9598007R5LSUJLGLS853, Bitcoin Store as MiCA CASP 984500NB7D12BC5B4A79, bitcoinmat as MiCA CASP 31570000GC0U68O6PA08 and bitflyer as MiCA CASP 984500D4465EFA89EF38.
The shape is consistent and the supervisor changes with the country of the entity, which is the part to read. It tells you which national authority the firm answers to, and therefore where a complaint would start. It does not tell you how custody, fees or withdrawal handling work, so use the register for the regulatory question and the Backpack review for the operational one.
Supervisors outside Europe
Outside the European registers, the naming changes and so does what the entry covers. Binance TH is registered with the Thai securities and exchange commission under 210280120004. Binance.US lists money transmitter licences across United States states and territories under NMLS ID 1906829, which is a different remit from a single national authorisation. asterium is registered with the National Agency for Advanced Projects of Uzbekistan under CS 0017.
Read these labels the same way: name the activity, name the authority, then decide whether that combination is the one protecting your deposit. A money transmitter permission and a crypto-asset service provider permission answer different failure scenarios.
A licence and a protection scheme are not the same entry
Alpaca's entry belongs to a different category from the rest. SIPC member 69928 is membership of a member protection scheme, which is a compensation arrangement rather than a supervisory licence, and the two answer different questions. A licence tells you there is a regulator to complain to. A scheme membership tells you what happens to a balance if a member firm fails. Neither substitutes for custody terms, which is why the Alpaca review is the place to read how the account handles assets.
Who is actually named on the terms
abarai takes a different shape again, and the difference is structural rather than cosmetic. Its Latvian entry, 40203730951, names an external partner as the party executing the exchange under the brand's terms. That is a workable arrangement, but it changes the question you should ask: the counterparty on your agreement may not be the brand you chose, so check who you are contracting with before you deposit. The abarai review covers the account itself.
A short routine before you deposit
Take the identifier from the firm's terms and search it in the register of the body it names. Note whether the activity matches what you are about to do, whether the entity is the one on your account, and whether any protection scheme entry exists alongside the licence. Then read the fee and custody pages on the review, because the register entry says nothing about either.
Apply the same routine to the wider shortlist rather than only the leaders. Start from where to buy crypto for the mainstream options, and check the decentralised exchange rankings as well, since an on-chain venue raises different questions about who holds the keys and which register, if any, applies.