(Reuters) - Retail brokerage TD Ameritrade Holding Corp AMTD.O said on Wednesday it has invested in a new cryptocurrency exchange called ErisX in a bid to offer clients digital asset investment options beyond the popular bitcoin.

TD Ameritrade clients can already trade bitcoin futures over the CBOE Futures Exchange. ErisX will allow clients to potentially trade other cryptocurrency futures, such as Etherium and Litecoin, said J.B. Mackenzie, TD Ameritrade’s managing director of futures and foreign exchange.

“It could open up additional cryptocurrency products on the future and spot side that our clients could potentially trade,” Mackenzie said.

Cryptocurrencies are virtual tokens that can be used as forms of payments on a variety of online applications. They can also be traded on dedicated online exchanges.

ErisX plans to launch spot trading in the first half of 2019, with physically settled futures to launch later in 2019, subject to regulatory approval, said ErisX Chief Executive Officer Thomas Chippas.

TD Ameritrade did not disclose the size of its investment in ErisX. It joins more than a dozen other investors, including Virtu Financial Inc VIRT.O, Cboe Global Markets Inc CBOE.N and Digital Currency Group in contributing to the funding round.