TOKYO, September 11 — Japan’s Nikkei stock index fell 2.8% on Friday, closing at its weakest level in several weeks and extending the volatile trading pattern that has defined the Tokyo market since late August. The selloff was driven by a jump in crude oil prices and renewed weakness in global technology shares, which pushed investors into a defensive position ahead of U.S. inflation data and next week’s central bank meetings. The Nikkei opened under heavy pressure after overnight Nikkei futures fell sharply and Wall Street weakened.
By 10 a.m., the index was down more than 1,600 points, and by 11 a.m. it was down more than 1,800 points, with Advantest alone accounting for a large part of the decline. The index remained weak into the close as investors reduced exposure before U.S. consumer price data.
Oil above $108 reshapes the calculus
Oil was the central shock. Brent crude traded above $108 a barrel, its highest level since May, after tensions between the United States and Iran intensified and investors feared deeper disruption to energy supplies. For Japan, which imports most of its energy, oil above $100 is already painful; oil above $108 is a direct threat to inflation, household spending, and corporate margins.
Higher crude prices feed into gasoline, electricity, aviation fuel, shipping, logistics, chemicals, and manufacturing costs. The impact is especially serious when the yen remains weak by historical standards, even though it has strengthened sharply from the 160 range seen earlier in the summer.
The yen traded around the mid-153 range against the dollar after rallying strongly in September. Its strength has helped reduce some imported inflation pressure, but the move has also hurt exporters and unsettled carry trades. On September 11, the market focused more on the oil shock and global rate fears than on any relief from the stronger yen.
A stronger yen normally supports importers, retailers, and household-facing companies by lowering the cost of overseas goods. But when crude oil surges, much of that benefit can disappear.
Investors therefore treated the yen’s strength as insufficient to offset the risk that energy prices will push inflation higher again.
Wholesale inflation keeps BOJ tightening in play
The Bank of Japan’s policy outlook became even more important after official data showed Japan’s wholesale inflation remained elevated. Producer prices rose 7.6% in August from a year earlier, reinforcing the view that cost pressure is still strong across the corporate sector. The data strengthened expectations that the BOJ will raise its policy rate from 1% to 1.25% at its September 17-18 meeting.
Reuters reported that markets have nearly fully priced in such a move, and analysts now expect the BOJ to continue tightening toward 1.75% in the second quarter of 2027. The BOJ kept rates unchanged at its July 30-31 meeting, but board member Hajime Takata dissented in favor of a hike to 1.25%.
Since then, Tokyo inflation, stronger wages, upgraded GDP data, yen volatility, and high producer prices have all strengthened the case for another increase. The central bank’s challenge is that inflation pressure is rising while markets are becoming more fragile. A rate hike may help anchor inflation expectations and support the yen, but it can also lift Japanese government bond yields, raise borrowing costs, and pressure growth stocks.
Japanese government bond yields remain close to levels not seen in decades. The 10-year yield recently moved above 3% for the first time since 1996, while shorter-dated yields have risen as investors price in faster BOJ normalization.
Higher yields support banks by improving lending margins, but they hurt high-valuation technology shares by raising the discount rate applied to future earnings.
Regional selloff cuts across Asia
The selloff was not limited to Japan. Asian markets broadly declined: South Korea’s Kospi fell 2.3%, Taiwan’s Taiex dropped 1.7%, Hong Kong’s Hang Seng slipped 0.8%, and Australia’s S&P/ASX 200 lost 1.2%. The regional weakness showed that investors were cutting risk across markets exposed to technology, global trade, and higher energy costs.
What to watch next: U.S. consumer price data and next week’s central bank meetings, including the BOJ’s September 17-18 gathering, where markets have nearly fully priced in a move to 1.25%. Whether Brent holds above $108 — and whether the yen’s September rally continues — will shape how much relief Japan’s import bill gets against the oil shock.
