Economics textbooks insist that stock prices reflect the future stream of a company’s profits on any given day. For all the brainpower devoted to these forecasts, however, they are essentially rough estimates of what may happen over the next twelve months and wild guesses about anything after that.

President Donald Trump stunned markets Wednesday by announcing 100% tariffs on imported semiconductor chips — but major chip stocks rallied. Taiwanese chip giant TSMC's stock closed 4.9% higher. In South Korea, Samsung Electronics ended 2.5% higher while SK Hynix reversed losses of over 3% in early trade to close 1.4% up.