President Donald Trump is bragging that Japan has given him, as part of a new trade framework, $550 billion to invest in the United States. It's an astonishing figure, but still subject to negotiation and perhaps not the sure thing he's portraying.

When President Donald Trump revealed that his administration had struck a "massive" trade and investment deal with Japan, he described it as "completed"—but it must still pass the Japanese parliament, called the Diet, which is riven with political turmoil.

The Japanese government, not companies, is poised to back U.S. infrastructure projects of the president’s choosing.