Taiwan chipmaker Global Communication Semiconductor (全新) is jumping sharply after a US brokerage nearly doubled its price target, good news for holders but risky for anyone buying now.

• A US broker lifted its target on the gallium arsenide chipmaker from NT$505 to NT$793, and the stock jumped again at the open.
• The reason is AI data centers: the broker sharply raised its forecasts for optical transceiver shipments through 2028, especially the fastest 800G and 1.6T parts.
• August sales beat expectations, up more than 70% from a year earlier, helped by better supply of indium phosphide wafers and more customers signing on.
• Earnings forecasts were raised hard, with profit per share seen more than doubling over the next two years.
• Foreign investors have been heavy buyers this month, though the stock has run up for days and chasing it here is the obvious trap.

Outlook: Sales are expected to keep climbing into year-end, but after such a fast run the stock is vulnerable to a sharp pullback.