After-hours trading starts at 4 p.m. U.S. Eastern Time after the major U.S. stock exchanges close. The after-hours trading session can run as late as 8 p.m., though volume typically thins out much earlier in the session. Trading in the after-hours is conducted through electronic communication networks (ECNs). The volume for a stock may spike on the initial release of the news but most of the time thins out as the session progresses. The amount of volume generally slows significantly by 6 p.m. There is a substantial risk when trading in illiquid stocks after-hours. So, it can be considered as a pretty risky trading style.