The Financial Post reports in its Friday edition that shares of cybersecurity companies have surged recently, driven by expectations that artificial intelligence threats will boost their business. A Bloomberg dispatch to the Post reports that some investors, however, are now questioning if these stocks have risen too much. A basket of cybersecurity stocks tracked by Goldman Sachs has more than doubled since hitting a low on April 10 after Anthropic restricted the release of its Mythos AI model over concerns it could power cyberattacks. Crowdstrike Holdings, Palo Alto Networks and Fortinet have all gained more than 130 per cent since then, putting them among the 10 best performers in the S&P 500 over that span. The Goldman basket, which closed at a record high on Wednesday, fell more than 1 per cent on Thursday amid a widespread sell-off across the tech sector. The rapid gains have made security stocks some of the most expensive in the market. Crowdstrike is priced at more than 170 times estimated earnings, which is second only to Tesla in the S&P 500. Palo Alto Networks is the fifth-most expensive in the index at 91 times profit projected over the next 12 months. Fortinet's multiple of 48 ranks 16th.