Since announcing his candidacy for President of the United States in 2015, former President Donald Trump presented himself as a business genius who could get the country back in fiscal shape, even promising to completely eliminate the national debt in just eight years.

In reality, the national debt grew by nearly $8 trillion, largely due to the Trump's Tax Cuts and Jobs Act of 2017, which Republicans continue to defend.

It shouldn't come as a surprise that Trump fell short on this promise, because despite images boasting the Trump family's material grandeur, television shows projecting the illusion of success on Trump's businesses, and ghost-written books about Trump's negotiatory acumen, the truth is that Trump's business skills are far from exception.

Trump has backed dozens of failed businesses, filed for bankruptcy multiple times, and been embroiled in thousands of lawsuits. The Trump Organization is under continued scrutiny from the New York Attorney General's office after a round of tax fraud charges.

Oh, yeah, and Trump remains hundreds of millions of dollars in debt.

But amid all of this, Trump has had a spot on the Forbes list of 400 richest Americans for the past 25 years—until now.

To make matters even more embarrassing, Trump's loss of the distinction wasn't due to others getting richer or some left-wing conspiracy against him—it was his own business decisions.

Forbes notes that Trump made the controversial decision to keep his investments after taking the White House, likely fearing stratospheric capital gains taxes, as his most lucrative investments were made long ago and have seen generous returns over decades.

But here's the kicker, according to Forbes:

"[W]hat would have appeared to be a huge sacrifice at first could have turned into a lucrative realignment. By plowing that $2.4 billion in an index fund tracking the S&P 500, for example, Trump's fortune would have ballooned to $4.5 billion by now, leaving him 80% richer than he is today. His refusal to divest, in other words, cost him $2 billion.

What's more, Trump could've completely avoided these capital gains taxes, as a statute in the federal tax code rewards government workers who divest their holdings with a certificate of divestiture allowing them to sidestep such taxes. Walter Shaub, who was the United States Office of Government Ethics director when Trump took office (now one of his biggest critics), told Forbes he "would have been happy to hand Trump a certificate of divestiture," even though it's unclear if the Internal Revenue Service would've honored it. But Trump's team never even inquired about it.

As Forbes points out, that was a huge mistake:

"If Trump had managed to avoid capital-gains taxes, he could have theoretically reinvested $3.5 billion into the S&P 500 on the day he entered the White House. In that alternate scenario, Trump would have been worth an estimated $7 billion by this September, when Forbes locked in estimates for its annual list, enough to earn a spot as the 133rd-richest person in the country. Instead, he's off the Forbes 400 for the first time in a quarter-century."

Social media users couldn't help but mock the former President—Shaub among them.

Others doubted he belonged on the list in previous years, after all Trump has been credibly accused of lying about his wealth specifically to secure a spot on Forbes' list.

That's gotta hurt.