Contra is not supported by the banks. The bank may affirm your BUY position for a settlement if you have sufficient investable amount but the SELL position will be revoked to cash settlement and is subjected to buy-in by SGX unless you have sufficient holdings in your account to satisfy your delivery obligations. Bank matrix for buy & sell on the same day with no holdings. Trade side DBS OCBC UOB Buy Remains as CPF SRS trade Revoke to cash Remains as CPF SRS trade Sell Revoke to cash Revoke to cash Revoke to cash