OpenAI may not be publicly traded, but the world’s most valuable startup is increasingly making waves in the stock market.Just last week, OpenAI sent shares of e-commerce companies Shopify Inc. and Etsy Inc. soaring after unveiling an instant buy option in ChatGPT. Then a blog post detailing new features the company is using internally sent a fresh wave of jitters through software stocks like Atlassian Corp., already reeling from fears about AI disruption.On Monday, it inked a deal with Advanced Micro Devic ...