Good morning and welcome to our rolling coverage of business, the financial markets and the world economy.

For the second day running, circuit breakers have been triggered on the Seoul stock exchange. But this time, it’s because the market is rising unusually quickly, rather than tumbling like it did on Monday.

Shares in South Korea’s chip giants are surging today, as investors pile back into the market after yesterday’s sell-off.

This rally is boosting optimism that the recent drop in tech shares is a blip, rather than the long-feared AI market crash.

Samsung Electronics’s shares are up over 9% today, while memory chipmaker SK Hynix have surged by 15%.

Those two heavyweight stocks have driven South Korea’s KOSPI up by 8.4% in Tuesday’s session, a day after it tumbled by 8%. Today’s market rally triggered successive temporary suspensions of program buy orders, known as “sidecars” in South Korea.

SK Hynix was boosted by a new multiyear partnership with Nvidia to develop next-generation memory for AI systems, whicch saw Nvidia’s Jensen Huang tour Seoul, meeting tech firms and handing out fried chicken to journalists:

Ipek Ozkardeskaya, senior analyst at Swissquote, points out that the wild swings in the KOSPI are unusual, and worrying.

A day with a rise or fall of less than 5% in the Kospi has become rare – a sign of just how volatile this market has become and, therefore, how much of the move is driven by speculation. Indeed, the Kospi’s volatility index keeps rising to unbelievable levels, suggesting that when the music stops, there will be carnage.

Anyway, today we continue to observe the tech-versus-non-tech narrative play out – technology attracting flows while non-tech pockets of the market lag behind.

That narrative will be tested in the coming months, though, as several massive tech firms attempt to float on the stock market.

Last night, OpenAI filed for its initial public offering – which could value the firm behind the ChatGPT chatbot at more than $1tn. That puts OpenAI in a race with fellow artificial intelligence pioneer Anthropic, and Elon Musk’s SpaceX which is due to float on Friday.

Kathleen Brooks, research director at XTB:

The OpenAI news means that we will hear more about how much revenue it is generating and how much cash it is burning through in the coming weeks.

2026 is set to be the ‘brat summer’* for these AI names, with their soaring valuations and big promises for how AI will change the world and send their revenues soaring.

[* For the benefit of any high court judges reading, here’s a guide to Charli xcx’s recent album, Brat]

The agenda

• 7am BST: German trade data

• 9:45am BST: Treasury Comittee hearing on Financial Inclusion Strategy

• 11am BST: NFIB’s US Business Optimism Index

• 1.30pm BST: US trade data for April