“Multibillion-dollar seed rounds in new start-ups that don’t have a product or technology or anything yet do seem a little bit unsustainable,” he said at the World Economic Forum in Davos this week, adding this may lead to “corrections in some parts of the market”.The comment comes as other tech leaders in Davos, such as Nvidia’s Jensen Huang and Microsoft’s Satya Nadella, batted off concerns of over-investment in the sector. Venture capitalists have rushed to buy into groups such as former OpenAI executive Mira Murati’s Thinking Machine Lab, which was valued at $10bn just six months after it was founded and despite giving few details on what it is building.