The rules have been established: "revolving lending for investment" is not allowed. Binance customer service's response can be summarized as follows: You can use borrowed USDC as collateral for other purposes. For example, if you have 100,000 USDC in your account, you can use it as collateral to borrow 78,000 USDT to buy spot or open futures contracts—no problem. This 100,000 USDC will benefit from the APR bonus. However, revolving lending is not allowed: Buy USDC > Collateralize USDC > Borrow USDT > Buy USDC Perhaps it's based on the total assets in the account to determine how much can be used for investment? Sorry I almost misled everyone yesterday. Thanks for pointing it out in the comments!