Robinhood, a free trading platform for stocks and cryptocurrency, is expanding its crypto offerings beyond Bitcoin and Ethereum to include Litecoin and Bitcoin Cash.

Robinhood Crypto has been steadily adding states where the service is available. Currently investors can buy and sell the four coins in 17 states, including California, New Jersey, Florida and Massachusetts, with more states becoming available in the future.

Robinhood began offering users the ability to trade Bitcoin and Ethereum — the top two cryptocurrencies by market capitalization — in February. Since then, investors have expressed interest in trading other cryptocurrencies, according to the company announcement.

Litecoin, the world's sixth-largest cryptocurrency, rose in value earlier this week on news that the Litecoin Foundation was partnering with payments platform TokenPay. Under the deal, the foundation received a 9.9% stake in WEG Bank in Germany. In return, Litecoin will aid in the development of TokenPay's cryptocurrency and business operations.

Last year Bitcoin Cash, currently the fourth-largest cryptocurrency by market capitalization, split from Bitcoin in a bid to return to an original vision of being a peer-to-peer electronic cash system. The result of a fork in the Bitcoin​ blockchain ledger, Bitcoin Cash prioritizes the ability to scale up and process transactions fast enough to be used for payments.

Robinhood's expansion into crypto, aimed at making trading cryptocurrencies easier and more accessible to investors, helped the company increase its reach to five million users across the platform. But all investors should be aware that investing in cryptocurrency is speculative and the market is generally unregulated.

Robinhood Crypto continues to offer users cryptocurrency market data and the opportunity to create price alerts for a total of 16 coins, including Ripple, Ethereum Classic, Bitcoin Gold, Lisk, and Dogecoin.