They go up or down because people buy or sell those stocks.
Good companies see their shares languish.
Bad companies become popular and their shares surge. Top executives from 415 companies gave financial presentations to these money managers in hopes of keeping current investors happy and drawing in new money. To a large degree, the mood of these men and women and their inclinations to buy or sell determines what happens to individual tech stocks and the market as a whole. They've been gathering at this conference for the past 29 years, and there is a strange familiarity to the market volatility. The disposition of money managers was, by and large, positive.