        // transfer strike to owner if put is expired or call is exercised
        if ((order.isCall && isExercised) || (!order.isCall && !isExercised)) {
            // send the fee to the admin/DAO if fee is greater than 0%
            uint256 feeAmount = 0;
            if (fee > 0) {
                feeAmount = (order.strike * fee) / 1000;
                ERC20(order.baseAsset).safeTransfer(owner(), feeAmount);
            }

            ERC20(order.baseAsset).safeTransfer(msg.sender, order.strike - feeAmount);

            return;
        }
        // transfer premium to whoever is short from whomever is long
        if (order.isLong) {
            ERC20(order.baseAsset).safeTransferFrom(order.maker, msg.sender, order.premium);
        } else {
            // handle the case where the user uses native ETH instead of WETH to pay the premium
            if (weth == order.baseAsset && msg.value > 0) {
                // check enough ETH was sent to cover the premium
                require(msg.value == order.premium, "Incorrect ETH amount sent");

                // convert ETH to WETH and send premium to maker
                // converting to WETH instead of forwarding native ETH to the maker has two benefits;
                // 1) active market makers will mostly be using WETH not native ETH
                // 2) attack surface for re-entrancy is reduced
                IWETH(weth).deposit{value: msg.value}();
                IWETH(weth).transfer(order.maker, msg.value);
            } else {
                ERC20(order.baseAsset).safeTransferFrom(msg.sender, order.maker, order.premium);
            }
        }
