MediaTek shares are surging after Nvidia backed the company with a big investment, good news for the chip designer and its shareholders.

• Nvidia is putting $3.5 billion into MediaTek convertible bonds, sending the stock straight to its daily limit.
• Broadcom's CEO Hock Tan named MediaTek as a rival for the first time, a rare public nod to its strength in custom AI chips.
• Big institutional buyers piled in this week, pushing the stock close to its all-time high.
• MediaTek is sticking to its forecast of more than $2 billion in custom AI chip sales in the fourth quarter.

Outlook: Foreign analysts see the closer Nvidia tie helping MediaTek win more big cloud customers, with 2028 chip revenue estimates likely to be raised.