Toyota, Honda and Nissan forecast big hits to their profits despite a trade deal that cut auto levies to 15 percent. The reduced rate has yet to be implemented.

Japan's promised $550 billion in U.S. investments under the trade deal struck last month will be determined by whether they will benefit Tokyo too, the Asian nation's top tariff negotiator said on Tuesday.

The new U.S.-Japan trade deal lowers tariffs and strengthens economic ties, helping challenge China's regional aggression and instability.