With President-elect Donald Trump pitching the US as a great place for business, firms around the globe are figuring out how to respond his call.

Japanese tech billionaire Masayoshi Son, a colourful character known as much for his major flops as his large accomplishments, presented one path on Monday, appearing with Trump at a press conference and pledging to invest $100bn (£79bn) over four years and make 100,000 jobs.

“He’s a great negotiator,” the CEO said, laughing on stage as Trump pressed him to double his commitment.

But plenty of questions remain about Mr Son’s assignment, especially in light of the lack of details he provided and the record of similar investments during Trump’s first term.

Mr Son has previously discussed the chance he sees in artificial intelligence, and Bloomberg reported in February that he was planning a $100bn chip assignment.

But his Softbank throng had only about a third of that, $30bn, in liquid assets earlier this year and its global reputation has taken large hits after previous bets, such as a major resource in co-working firm WeWork, imploded.

With the cameras rolling at Mar-a-Lago, Mr Son avoided giving specifics about how he would fund his commitment.

Nor did Trump demand details, casting the pledge primarily as a sign of a wider renewal in business optimism, which has been reported in surveys in recent weeks.

“This historic resource is a monumental demonstration of confidence in America’s upcoming,” the president-elect said.

Trump has indicated that when he returns to the White House he plans to use the bully pulpit to court foreign resource.

His campaign promises to slash both taxes and regulations have already boosted Wall Street and charged up large business to pursue large-scale ambitions.

Specifically, Trump has said he would cut taxes for companies that make products in the US and speed approvals for firms investing $1bn or more.

Investors expect him to green-light takeovers and pull back on enforcing antitrust laws, as well.

Still, there are concerns about Trump’s campaign promises to crack down on immigration, which could affect the workforce, and raise tariffs on imports from China, Mexico and Canada. On top of that, he has discussed rolling back manufacturing and vigor incentives put in place by President Joe Biden, which some investors like.

Political leaders from both parties often promote business investments and will often receive some capitalization when those ventures boom. President Joe Biden, for example, visited projects by companies such as chipmaker TSMC to highlight historic incentives the government approved for green vigor and high-tech firms.

Monday’s occurrence recalled pageantry familiar from Trump’s first term in office, which was punctuated by high-profile announcements of investments. Many of those planned projects had been in the works already or were hazy in their chances of becoming reality.

Those included Taiwanese semiconductor giant Foxconn’s plans to construct up a technology park in Wisconsin, which Trump had boasted would become the “eighth wonder of the globe”. Instead of creating more than 13,000 jobs and spending more than $10bn, the business created less than 1,000 jobs and spent around $1bn, according to CNBC.

Trump had also said he would save a failed car factory in Lordstown, Ohio, with an electric vehicle commence-up backed by Foxconn and had celebrated promises to make a million jobs over five years made by Alibaba’s Jack Ma.

The car business – Lordstown Motors – filed for financial setback and reorganized to become Nu Ride Inc earlier this year.

Meanwhile, Alibaba has said it “supported” 403,000 US jobs in 2022, five years after Mr Ma made his commitment.

Mr Son’s connection with Trump also dates back to his first election.

Shortly after Trump took the White House, the two men appeared together to discuss $50bn Mr Son planned to invest in the US, as his firm was evolving into a benevolent of technology assignment-fund firm.

Its current holdings include US telecom firm T-Mobile and UK microchip designer Arm.