What time do options positions automatically close on the expiry date?

[OptionsExplorer]

Hello, I am new to options trading and held a short straddle position (sell call at 7100 FTSE100 and sell put at 7100 FTSE 100 both at 17th December 2021 expiry date).

I noticed that the positions were automatically closed at 10.27Am and 10.28AM on 17th December (so that corresponding buys took place at that time). Is there a time range when these auto-closes occur? It took me by surprise as I was expecting the auto-close to happen closer to end of market time rather than randomly in the morning. Screenshot below. 

Would appreciate someone throwing some light on this. Many thanks!

Riya

[AndaIG]

Hi @OptionsExplorer

Thanks for the query. 

Assuming you are referring to the FTSE 100 Monthlies,  the expiry is the 3rd Friday of each month. The auto-close will occur after the auction period (10:10-10:15 am UK time) once we have received the official settlement from the exchange. We display expiry dates on the platform. Please see the below screenshot:

All the best, 

Anda