HI Mav, Some actually don't as they don't allow overnights... only intra-day pairs... And some charge high interest rates on the overnights as well. So I guess the question should be who allows overnight pairs..lol Nick
Honestly I think most firms do allow overnight pair trading. Obviously not the sub LLC firms that want you to put down 5k and pull the lever. But most "real" firms allow that. Hell, almost every prop firm in Chicago exclusively trades pairs in one form or another whether it be futures or stock. I honestly think you would have a harder time finding a firm in Chicago that trades flat price.
Not sure if the ones I was checking were sub llc's... But I know that some did allow pairs but with only 5 x overnight leverage and /or very high interest. BTW, sent you a pm Mav...