United Kingdom, July 31 -- Samsung's unexpected $16.5 billion AI chipmaking deal with Tesla has boosted the company's stocks by nine per cent.

The surge brings Samsung's gains in July to over 20 per cent, setting the stock on course for its best month in more than four years.

The agreement marks a significant shift for Samsung's foundry business, which has struggled in recent years to compete with Taiwan Semiconductor Manufacturing Co. and has relied heavily on internal orders.

Analysts at Citigroup noted that the deal signals a transition towards deeper external partnerships, a move that could boost Samsung's credibility and expand its client base.

"I think market basically paid not even zero value - negative value - on foundry busin...