(Reuters) -An emerging U.S.-Japanese trade deal could unlock major investment, avert a potential shock to the global economy and may deliver political wins for both U.S. President Donald Trump and Japanese Prime Minister Shigeru Ishiba, though many specifics of the agreement remain unclear.

Japanese Prime Minister Shigeru Ishiba has vowed to remain in power to oversee the implementation of a new Japan-U.S. tariff agreement.

The right-wing populist party Sanseito made big strides in parliamentary elections in Japan, capitalizing on concerns about the economy, immigration and overtourism.

Shigeru Ishiba denied he had decided to quit after a source and media reports said he planned to announce his resignation to take responsibility for a bruising upper house election defeat.

The reports come after Trump announced a trade deal with Japan, and days after Ishiba’s governing coalition lost its majority in the country’s upper house.

As part of a trade deal reached this week, Japan agreed to invest $550 billion in projects across strategic U.S. industries, including energy, semiconductor manufacturing and shipbuilding. The White House said Trump would have final say over where the money goes and that the U.S. would keep 90% of profits on any investments.

By Satoshi Sugiyama and Leika Kihara TOKYO (Reuters) -Japanese Prime Minister Shigeru Ishiba plans to announce his resignation by the end of next month, the Mainichi newspaper reported on Wednesday. Ishiba is facing growing opposition from within his Liberal Democratic Party for his vow to stay in power despite the ruling coalition's bruising defeat in Sunday's upper house election.