Kospi falls 14.5% in a week to 5,668, 38% below its June closing high, the worst week since 2008

The Kospi closed Friday at 5,668.05, down 14.5% from the 6,625.93 close on Thursday, October 8, the last session before this week's start (October 9 was a holiday). Reuters, in a report carried by The Star, said the index was heading for its biggest weekly loss since October 2008 and its third straight weekly decline, as investors worried about whether the global AI investment boom can be sustained.

The closes

Source: Yahoo Finance daily closes. Reuters reported Thursday's drop as nearly 8% and the longest losing streak, seven sessions, since September 2024.

How far from the top

On Yahoo's data the Kospi's highest close in the past year was 9,114.55 on June 22, so Friday's close was 37.8% below it. Some videos cite a 9,385 record; we could not match that figure to a closing price, so we use the closing high. Reuters also reported foreigners net sold 307.8 billion won on Friday morning, the won at 1,346.1 per dollar, and the finance ministry promising closer monitoring of bond, currency and money markets.

The chip stocks did the damage

Using the same Yahoo closes, Samsung Electronics fell 17.7% over the week, from 262,000 won to 215,500 won, and SK Hynix fell 24.3%, from 1,681,000 won to 1,272,000 won. Japan's Nikkei 225 fell 5.4% over the same stretch, from 69,042 to 65,324. Because two memory makers carry so much of the Kospi's weight, a rout in AI-linked chips shows up in the whole index, which is how a market can fall 14.5% in a week without a local economic shock. Our earlier report covers the single-day damage to SK Hynix, Samsung and Advantest.

Bonds and the won

Reuters reported South Korea's three-year government bond yield at 3.877% and the 10-year at 4.205% on Friday morning, with the won weaker at 1,346.1 per dollar. For a Korean exporter or an importer paying in dollars, a weaker won raises the local cost of imported inputs just as equity wealth shrinks, which is why the finance ministry framed its monitoring around spillovers into bond, currency and short-term money markets. Those figures are Reuters' intraday readings, not closes.

What it means outside Korea

The same fear about whether AI spending can be financed hit Wall Street's chip names on Friday, and it is the reason our semiconductor ETF check shows SMH 14.9% below its October 5 high. On Monday the Kospi rose 1.8% to 5,768.01, a bounce that leaves it about 36.7% below the June closing high. One strong day does not change the week's record: Reuters said the index had fallen for three straight weeks.

Sources: Reuters via The Star; Yahoo Finance. This is market information, not investment advice.