President Donald Trump’s fast-approaching “Liberation Day” sent stock markets swinging sharply worldwide on Monday. On Wall Street, the S&P 500 rose 0.6% in another roller-coaster day, after being down as much as 1.7% during the morning. The reversal helped the index shave its loss for the first three months of the year to 4.6%, making it the worst quarter in two and a half years. The Dow Jones Industrial Average also swerved higher after erasing an initial loss, and it climbed 417 points, or 1%. Slides for Tesla, Nvidia and other influential Big Tech stocks, though, sent the Nasdaq composite...