Intercontinental Exchange Group plans to launch a new trading-only exchange in the second quarter, according to a regulatory filing.

NYSE National would be ICE’s fourth equity-trading venue and the 13th U.S. equity exchange. It will be trading-only and not have listings, the exchange operator said.

The new exchange may boost ICE’s equity market share in its ongoing battle with large rivals Nasdaq and Cboe Global Markets.

With a full field of exchanges plus several dozen dark pools and other off-exchange venues, fragmentation continues to vex market participants. Exchange operators seeking to add incremental market share say each new exchange is differentiated in some way and adds choice and order types; traders generally say the added cost and complexity associated with a new venue offset any benefit.