A wave of Big Tech companies reported quarterly earnings in recent weeks — including six of the so-called Magnificent 7 firms — shortly after Chinese AI startup DeepSeek rattled the stock market as investors saw its new, cheap artificial intelligence models as an ominous sign for US tech stocks. DeepSeek’s innovations so shook the US tech industry that AI darling Nvidia (NVDA) saw $600 billion shaved off its market cap in a single day — the biggest loss in stock market history — as investors worried Big Tech would slow its spending on AI hardware. Now, some US lawmakers are…