Leonardo SpA said Tuesday that it has agreed to merge its U.S. business with Rada Electronic Industries Ltd. in an all-stock transaction that will create a newly listed company.

The Italian helicopter maker’s LDO, +1.84% Leonardo DRS subsidiary will acquire 100% of Nasdaq-listed, Israel-based defense-technology company Rada RADA, -1.19% in exchange for a 19.5% equity stake in Leonardo DRS for Rada shareholders. Leonardo will retain the remaining 80.5% stake in Leonardo DRS, it said.

The new entity will begin trading in New York and Tel Aviv under the ticker symbol DRS when the transaction closes, likely in the fourth quarter of this year subject to approvals, Leonardo said.

Rada has a market capitalization of $578.6 million, according to FactSet, and is a leader in mini-tactical radars and serves attractive, high-growth markets, Leonardo said.

The transaction will give Leonardo a presence in Israel and help it develop internationally, the company said.

Write to Joshua Kirby at joshua.kirby@wsj.com; @joshualeokirby