Seoul markets fall over 4% as tech shares drag

Imagine a giant scoreboard for South Korean companies called the stock market.

On Thursday, that scoreboard went down a lot — more than 4 percent.

The main reason was worries about technology companies and the money they spend on AI.

AI is a kind of computer brain that can learn, and building it costs a lot of money.

Some people are not sure those companies will earn enough from AI to cover that cost.

Earlier in the week, the scoreboard had gone up because those worries seemed smaller.

But on Thursday the worries came back, and big technology stocks pulled the whole market down.

To help calm things down, the exchange paused automatic computer trading for five minutes.

Even though the main index fell a lot, more stocks actually went up than down.