Not that long ago Oracle was seen as the best way for public-market investors to play red-hot start-up and ChatGPT maker OpenAI, which has committed to buy $300 billion in cloud services from Oracle. Sure enough, the cost of credit default swaps on Oracle debt, essentially insurance against a potential default, have risen to their highest level since the 2008 financial crisis. The Nasdaq Composite finished the week down 1.6% after Friday’s 1.1% slide.