Trump has just two winning stock market years now for his four-year term. The S&P 500 rose 19.4% in 2017, fell 6.2% in 2018, rose 28.8% in 2019 and is now down more than 21% in 2020.

For the S&P 500, the more widely watched market index, the rally has retreated from a gain of 58% to one of 18% since the president's victory over Democrat Hillary Clinton. The S&P 500 is up 12% since the market's close one day before Trump's inauguration.

What was once a 61% Dow gain since Trump's election has evaporated to far thinner 18.2% rally as the index fell from an all-time high of 29,568 on Feb. 12 to around 21,600 by midday Thursday. The gain in the Dow is just 9.8% if you measure from Trump's inauguration day more than three years ago.

The month's historic plunge in the stocks — including Thursday's eye-popping 8% drop — has dramatically slashed the market gains seen since President Donald Trump's election

By one measure, the sell-off has erased all of U.S. market cap gains since Election Day 2016, wiping out more than $11 trillion in value in less than one month as measured by the Russell 3000 index, according to Bespoke Investment Group.

On Feb. 19, total U.S. market value was just over $35 trillion, but it's since fallen to $23.8 trillion — the same as it was on Nov. 8, 2016, according to Bespoke.

The Russell 3000 index is a barometer of the total stock market, encompassing shares of small caps, which have been harder hit during this market sell-off.

"At this point in time, all of the market cap gains seen since President Trump's election victory have been wiped out," wrote Paul Hickey, founder of Bespoke.

The dramatic fall in Dow gains since the president's election came amid the index's single-worst day on Wall Street since the 1987 stock market crash known as "Black Monday." At the latest reading, the Dow was down 2,180 points, or 9.28%.

The S&P fared little better and was on track to post its worst week since October 2008 and the peak of the financial crisis. The Dow is down 4,400 points, or 17%, over the same time and also on track to clinch its worst week since 2008. Both indexes were set to close in a bear market, defined as a decline of 20% or more from recent highs.

As for Trump, he has blamed both the threat of 2020 Democratic candidates as well as the coronavirus for the month's steep declines.

The president delivered an Oval Office address on Wednesday, but failed to quell concerns over the possible economic slowdown stemming from the coronavirus, leading to the historic moves in U.S. markets.

Trump repeated on Thursday that the market would be "just fine."

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