"Big market delusion" occurs when a new market opens up and shows signs of disrupting an existing industry, and suddenly, every company within the new market is on investors' watchlists. For example, the electric vehicle industry has exploded in recent years, and every new electric automaker seems to catch investors' eyes. As a result, share prices for these companies are up across the board, which is where the big market delusion comes in. This Research Affiliates article explains why the electric vehicle market has exploded — and why it may be unsustainable over the long term.