Got it, thanks! That makes sense.
In case anyone with similar questions finds this thread, I'll add that the other issue I noticed with placing MOO orders on a paper trading (IBKR) account is that ~half of those I tried were not filled. One was a partial fill.
Very happy to know this is...
I am debugging a market-on-open (MOO) order using the IBKR API (currently just in paper trading).
Everything I read suggests using MOO should get a fill at the open price. I'm getting substantial slippage between the ticker.open price (in the IBKR API) and the price IBKR says that I actually...