Maximum borrowable amount. Can be "0" when spot margin mode is off, or when no collateral coins are enabled. The app can still show a borrow amount after a collateral coin is selected. Undocumented; Bybit API staff confirmed this on 15 Oct 2026. Check getSpotMarginState(), setCollateralCoin() (POST /v5/account/set-collateral-switch), and toggleSpotMarginTrade() first.
