Subaccounts in your Casa App allow you to have multiple multisig keysets (wallets) within a single Casa account. Subaccounts allow you to safely keep your bitcoin separated in different pools.
"Why would I use subaccounts?"
While having a subaccount in your Casa App is optional, there are several reasons why you may want to have an additional keyset in your app.
- You have bitcoin owned by different legal entities and need to keep those separate for tax reasons
- You’re HODLing for different different goals or different people, and want to track these balances individually
- You’ve earned some BTC pseudonymously (i.e. from mining), and don’t want to mix that with coins you’ve bought on an exchange
"How do I create a subaccount?"
Since you'll be using the same keys for your subaccount as you use for your primary multisig account (you won't be adding additional keys for this new wallet), you'll first need to create your primary Bitcoin multisig wallet.
Once your primary multisig wallet is set up (or if it's set up already), you would:
- Swipe up on your multisig keyset
- Tap the “+” button
- Give your subaccount a name (you can change this later)
Your subaccount is now ready to deposit funds!
"How do I spend from my subaccount?"
Subaccounts are secured using the same keys as your primary wallet. Therefore, when you need to spend funds from your subaccount wallet, you would send just as you would normally. You will still need to apply multiple signatures to the transaction in order for funds to be sent from any multisig wallet.
"How many subaccounts can I have?"
How many additional wallets you can have depends on your Casa membership level.
- Gold members have access to their primary wallet, plus one subaccount (2 wallets total).
- Platinum members and Diamond members have access to their primary wallet, plus 4 subaccounts (5 wallets total).
"Can I use subaccounts to manage bitcoin held in my IRA?"
We recommend checking with your tax professional first.
To be safe, our guidance is to store your personal bitcoin and any bitcoin in your IRA in fully separate Casa accounts and to avoid using any personal funds (i.e. a personal credit card) to pay for your IRA membership.
"How do subaccounts work technically?"
When you create a Casa multisig account, Casa imports the root extended public keys (‘root xpubs’) for each and every hardware device (Trezor, Ledger, mobile phone, etc.). Casa App uses these to create new receive addresses every time you make a deposit.
When you create a subaccount, Casa derives an unused set of child extended public keys (‘child xpubs’) from each of these root xpubs. (This follows the BIP 32 standard.) All the receive addresses in the new subaccount will be created from this set of child xpubs. And if you create a second subaccount, yet another set of child xpubs will be derived from the root xpubs and all addresses in that subaccount will be derived only from that second set of child xpubs.
The bottom line is that even though your subaccounts are all managed by the same hardware devices, they are each based upon distinct sets of xpubs and the resulting addresses create no data on the blockchain that can be used by an observer to correlate funds in different subaccounts as long as you don’t send funds from one subaccount to another.