IB use custodian banks but even if IB acts custodian, your assets are separated/recoverable in case of IB bankruptcy but ensure that you have a cash account not margin etc.. The most significant risk is insider fraud but it is unlikely because IB is a public company. They're audited more and strictly and everyone can access their financials.
https://www.interactivebrokers.com/en/index.php?f=2334
Another option is Saxo Bank. They use Citibank as custodian. If Saxo︀ bank fails, you should able to recover your funds from Citibank. If Citibank fails, you︁ should be able to recover your funds because custodian accounts are not assets of bank/financial︂ institutions. This means creditors cannot access to custodian accounts. Custodian accounts are segregated. The downside︃ of Saxo Bank is they're not a public company and smaller than both IB and︄ SQ.
You can also go with tier 1 banks like Citibank IPB, HSBC, BNP Paribas︅ but expect 0.50% custodian fee + 1% transaction fee but still not guarantees that your︆ assets will hold with the bank. Even banks use different custodian banks depends on asset︇ origin, market, currency etc...
https://www.interactivebrokers.com/en/index.php?f=2334
Another option is Saxo Bank. They use Citibank as custodian. If Saxo︀ bank fails, you should able to recover your funds from Citibank. If Citibank fails, you︁ should be able to recover your funds because custodian accounts are not assets of bank/financial︂ institutions. This means creditors cannot access to custodian accounts. Custodian accounts are segregated. The downside︃ of Saxo Bank is they're not a public company and smaller than both IB and︄ SQ.
You can also go with tier 1 banks like Citibank IPB, HSBC, BNP Paribas︅ but expect 0.50% custodian fee + 1% transaction fee but still not guarantees that your︆ assets will hold with the bank. Even banks use different custodian banks depends on asset︇ origin, market, currency etc...