LONDON : European companies that are spending big on generative artificial intelligence need to start showing returns on their massive outlays by next year, or risk investors losing patience after they paid sky-high prices to join the market boom. AI-exposed stocks have been caught in a down-draught with broader equity markets in recent weeks as recession fears rise, adding to pressure on the sector since January, when the launch of low-cost Chinese AI model DeepSeek spurred a tech selloff.