The Globe and Mail reports in its Saturday edition that it might be wise not to sell your SPF 50 just yet. The Globe's Tim Shufelt writes that while summer is fading, the stock market remains hot. Since spring, stocks have rebounded from tariff-induced despair to the exuberance we see today. The S&P 500 index is up 30 per cent from its low point. In financial markets there is the whiff of excess. Retail investors are all in. Valuations on U.S. stocks are towering. As well, the artificial intelligence hype machine has drowned out concerns about tariffs and trade wars. It is starting to feel a lot like 2021, when a booming bull market morphed into a speculative hysteria of meme stocks and non-fungible tokens. A harsh reckoning soon followed. The current cycle could follow the same path. One thing is clear, however. There will be far fewer winners of the AI revolution than investors are currently clamouring for. When the stock market coalesces around a transformative technology like AI, it is easy for companies to bask in the glow of the new thing. A mass culling in AI is inevitable, as a recent MIT paper revealed that 95 per cent of businesses studied saw no return on their generative AI investments.