The Globe and Mail reports in its Saturday edition that it is hard to overlook the disturbing fact that U.S. corporate profits, as a percentage of the overall economy, have surged to levels not seen since 1929. The Globe's Ian McGugan writes that profits, strictly calculated, accounted for about 5 per cent of the U.S. economy a generation ago. They now make up more than 9 per cent. Yes, profits are a wonderful thing. But unusually high levels of profitability often precede a crisis. That was the case in 1929, on the eve of the Great Depression. It was also the case in the mid-1960s, just before inflation took off and stock prices went into a two-decade funk. Don't expect competition to come to the rescue. Google, Meta and Nvidia enjoy an unusual amount of market power. They can't be easily undercut by upstarts. At one time, companies such as the original General Motors, AT&T and Standard Oil also seemed to be impregnable monopolies. Yet even these historical titans eventually saw their advantages erode. Changing technology played a role in humbling them. So did politics. And keep in mind that while profit margins are rising for the Magnificent Seven, they are flat for the other 493 companies in the S&P 500.