A video board projects the day's numbers after the closing bell of the Dow Jones at the New York Stock Exchange on March 31, 2017.

On its face, the tweet was one of the most innocuous President Trump has ever sent—a plain-vanilla reminder early Friday morning that the monthly federal jobs report was coming out in an hour’s time.

“Looking forward to seeing the employment numbers at 8:30 this morning,” the president wrote at 7:21 a.m. ET.

No exclamation points. No all-caps. No gratuitous insults, partisan jabs, or demands that his opponents be investigated.

For Trump, this was boring, even low-energy. Except this nothing-burger of a tweet may have moved billions, if not trillions, of dollars on the global market and sent the community of economists and investors who scrutinize the jobs report into a tizzy.

At precisely 8:30 a.m. ET on the first Friday of every month, the Labor Department’s Bureau of Labor Statistics releases a summary of employment in the United States. The data is culled from two separate reports that show, among other things, how many jobs the private and public sectors gained or lost in the previous month and whether wages went up or down. The headline figure is almost always the national unemployment rate, which in May fell to an 18-year-low of 3.8 percent.

To say the jobs report is closely held is an understatement. It is treated as a state secret until the moment the data is released to the public, so that no stock trader—whether in the U.S. or abroad—can get even the slightest advantage over anyone else. Reporters who cover the monthly jobs report are shepherded into a locked room at the Labor Department and instructed to leave their cellphones outside until the clock strikes 8:30 a.m., at which point market-watchers see a flurry of tweets and emails with the key figures.