Whats the difference between "fill outside RTH" and "allow preopen"

Hi

IF i want to a trade to execute at 4am and still be sleeping which is my best option on IB? I see 2 options...""fill outside RTH" and "allow preopen""

whats best and whats the difference? thank you

 

Outside RTH means pre-open + after-hours.
I thought this was so logical it shouldn’t need an explanation

 

thanks, so why would you want only pre-open? technically pre-open is still after market hours from the day before lol

 

I guess you could use it as a timer to expire your orders at the end of day. Many people don’t want to trade or hold their positions overnight, which includes after-hours when some earnings are announced, Asia starts trading, middle-east stirs things up, and a lot of other stuff can happen. Pre-open imay be a good time to decide what to trade.

 

Perhaps the phrasing should be "pre-open only"??... though hard to imagine the strategy for that.

 

Pre open - market is closed and is about to open

outside RTH - market is open in say Asian and Eur sessions
RTH - market is open in say US session

 

This is only correct for US stocks. The RTH for e.g. European stocks is different. And if you start to look in IB's determination of RTH for futures you'll find a myriad of start times and end times.

 

right.
different brokers / exchanges use different terms.
some even use terms like T session, T+1 session, T + 2 session etc etc