SEC Commissioner Hester Peirce raises six concerns regarding 23/5 US stock trading

On Sept. 17, SEC Commissioner Hester Peirce addressed the shift toward a 23-hour, 5-day trading model in US stocks. While overnight trading currently accounts for less than 1% of total NMS volume, Peirce raised concerns regarding liquidity fragmentation, best execution obligations, the impact on corporate disclosure, and whether the EDGAR system requires updates to handle overnight filings.