Mistake during 0DTE SPX call spread

[vintrader]

 

Sold a SPX call credit spread (6685/6700) for a net credit of $0.40 ($0.67 - $0.27) with same-day expiration (Oct 17).

SPX was around 6645

I opened a "Buy to close" for SPX6685 with a stop price of $2:00. At around 2:10 PM, When the SPX touched 6658, the SPX6685 Call was around $1.8. I was not ready to loose money so I canceled my order. I was glued to the screen just hoping that SPX won't rise any further. It went to 6672 at around 3:10 PM and the SPX6685 Call was around $6.00 at that point. I was down almost $550 at that point. SPX came back to 6664 and my SPX6685 call was around 1.3. I was happy that I dodged a bullet but knew I was very stupid. Later around 3:20 PM, SPX went to 6678.88 and the SPX6685 call was back to $4. Still I didn't do anything. Was just hoping the day will end somehow. For next 40 mins, SPX hovered around 6670.

 Somehow, I ended the day without a loss with SPX at 6664.

 What should have been my strategy? When should I have closed my position and how much risk should I take? Any better strategy for same-day expiration SPX spread?

 

[Kim]

A better strategy would be not to trade options that expire the same day. Extremely risky.