I recently opened a Marcus bank account (for the purposes of then transferring funds to another account and triggering a Direct Deposit). I funded with a transfer from Charles Schwab and it was taking forever for my funds to be available so I inquired how long it would take for them to available.
Turns out that funds become available in your account 5 business days after they’ve been deposited into your account.
Hope this proves to be helpful for anyone else looking for this information!