股指期货与利率期货都不克交割，书上言

金融期货又不止股指期货和利率期货

it depends on your underlying assets of the future contract

If the underlying assets are stock, then when you exercise the future contract

it will not be the cash, stock shares instead.

What you mentioned above, like interest rate future

the underlying assets are capital

therefore when you exercise the future contract, you have to deal with capital