Anthropic's primary backers, Amazon and Google, are the most likely acquirers. An acquisition announcement would cause significant volatility in their stock prices (often a short-term dip for the acquirer, but potentially a long-term strategic positive; or volatility due to antitrust scrutiny). This would also impact sentiment across the broader AI sector and the Nasdaq 100. Amazon, being the largest external investor, would likely see the most direct stock impact.