if your salary is 3000, 20% of it will to CPF(600), company will give 14.5% more to CPF(435). so you can got total earning is 3435. all PR follow the same rules. but in you bank you can take is 2400 (3000-600), the other 1035 will keep in CPF, can't be withdraw if you are PR status. if you cancell you PR go back to china you can take out all your money.