Nasdaq Inc plans to introduce 24-hour trading on its flagship U.S. exchange to capitalize on growing global demand for U.S. equities, a senior executive said in a social media post on Friday.

When we look at stock trading activity, based on time stamps reported to the SIP (Chart 2), we see that the period from 4 p.m. until 6 p.m. is still reasonably busy, and residual trading appears ...