Taiwan's stock market sank more than 500 points, a bad day for investors in the island's big tech names after a wobble in US AI stocks.

• TSMC, MediaTek, Foxconn and Delta all fell, pulling the index below 49,000.
• The trigger came from New York, where AI stocks pulled back on word that OpenAI's revenue run-rate is far smaller than earlier reports suggested.
• Foreign investors sold heavily and piled into short bets, leaving the mood tilted toward more selling.
• Pegatron bucked the trend and jumped to its daily limit, while Pou Yuen-style small caps face profit-taking after recent run-ups.
• Foxconn, Delta and Quanta were also named in a new US trade commission patent probe that could take over a year to resolve.

Outlook: US inflation data due this week will set the tone, and TSMC's earnings briefing on Thursday is the next big test — analysts have been raising their price targets going in.