You are not able to earn interest in trades between your BTC Transaction and USDC Transaction Accounts. If you want to earn interest on your BTC after the trade, you must transfer the BTC balance on your BTC Transaction Account to your BTC Growth Account.
Every time you place a trade between your BTC Transaction and USDC Savings Accounts, your USDC starts earning interest immediately after the trade is settled as it goes directly to your interest-earning USDC Savings Account. If you want to earn interest on your BTC after the trade, you must transfer the BTC balance on your BTC Transaction Account to your BTC Growth Account.
Please note that interest-earning Growth Accounts are not available for U.S or Canadian residents.