Just caught wind of something interesting in the market infrastructure space. Nasdaq is apparently working on a proposal to shake up stock trading hours in a pretty significant way. They're planning to pitch this to the SEC, and if it goes through, it could fundamentally change how people trade stocks and ETPs.

So here's what they're proposing - instead of the current setup where you get about 16 hours of trading per day, five days a week, they want to introduce what they're calling the 5X23 model. Basically, it's trying to extend trading to 23 hours a day. The way it would work is pretty clever actually. You'd have a daytime session running from 4 a.m. Eastern Time all the way to 8 p.m., which keeps the familiar pre-market, regular market (9:30 a.m. to 4 p.m.), and post-market structure intact. Then there's a nighttime session that kicks in at 9 p.m. and runs until 4 a.m. the next morning.

The weekly schedule under this 5X23 framework would start Sunday at 9 p.m. and wrap up Friday at 8 p.m. after the daytime close. One thing worth noting - any trades between 9 p.m. and midnight get counted as the next calendar day's trading, which is a bit of a technical nuance but important for settlement purposes.

What's interesting here is that this could potentially level the playing field a bit. Right now, international traders dealing with time zone differences are pretty limited in when they can actively trade U.S. equities. The 5X23 model would give way more flexibility. Whether the SEC actually approves this is another question entirely, but it's the kind of proposal that could reshape market structure if it gets greenlit.