With the launch, Robinhood will be the first major U.S. retail broker to allow 24/5 trading of single-name stocks, while brokerages including Charles Schwab Corp and Interactive Brokers Group Inc currently allow near-continuous trading in ETFs and some single-name stocks.

Here are some details on when retail investors can trade stocks:

* Regular U.S. trading hours are between 9:30 a.m. and 4:00 p.m. Eastern Time (1330-2000 GMT) during the trading sessions of major exchanges, such as Intercontinental Exchange Inc's New York Stock Exchange, or the Nasdaq.

* Most major U.S. brokerages offer extended hours trading, with premarket trading starting at 4 a.m. until the open, and after-hours trading between the market close and 8:00 p.m.

* Robinhood said it will begin its foray into 24/5 trading with 43 ETFs and individual stocks between 8 p.m. Sunday until 8 p.m. Friday, with more securities to be added over time.

* Schwab's TDAmeritrade offers 24/5 trading on a couple dozen ETFs through its thinkorswim trading platforms.

* Interactive Brokers offers overnight trading in 75 stocks and exchange-traded products from 8:00 p.m. ET to 3:30 a.m.

* Traders placing orders at retail brokerages outside of regular trading hours can only submit limit orders, which must be executed at specific price or better, as opposed to market orders, which trade immediately.

* Risks of overnight trading include less available liquidity, so trades might not get completed, volatility could be higher, spreads could be wider, and prices might vary from the regular trading session.

(Reporting by John McCrank; Editing by Marguerita Choy)