Ah, the financial markets. A bastion of rational thought, meticulous planning, and predictable reactions to geopolitical stability. Or, at least, that’s what the textbooks say. In the era of Donald J. Trump, however, this venerable institution often resembles a particularly volatile carnival ride, powered by presidential pronouncements and the collective shrug of investors who’ve learned to expect the unexpected. Forget economic indicators; the real market mover is often a social media post, a televised thr ...