The DeepSeek sell-off could soon mean a buying opportunity in Amazon and Broadcom , according to Hightower Advisors’ Stephanie Link. Stock futures are tumbling Monday after Chinese startup DeepSeek debuted a potentially competitive artificial intelligence model at a lower cost than OpenAI, spurring investor fears of an impending burst in the AI bubble. The S & P 500 soared more than 20% both in 2024 and 2023 in large part because of bets that AI would unlock large markets for the…