The global stock market has gotten increasingly unstable. In the United States, it’s nothing out of the ordinary anymore if the Dow Jones Industrial Average swings down more than $200 a day, and as a corollary to that, the Nikkei Index has fallen approximately 7 percent thus far this month.

A sense of wariness toward the sudden deceleration of the global economy can partially explain this instability. Last week, the finance ministers and chairpersons of the central banks of G20 nations and regions shared an understanding of the risk of future downswings in the global economy.

The flagging performance of major U.S. companies — which are the sensitive mirrors of the state of the global economy — makes it clear that risk is becoming salient.

Semiconductor manufacturing company Microchip Technology, for instance, has announced that its third-quarter sales — July to September — seem to have fared below expectations. Major automaker Ford Motor Company has laid out a forecast that it will take more time to improve its profitability in Europe, where demand is still sluggish.

Having said that, the performance of U.S. companies does not have to be taken too seriously. As of now, the third-quarter net sales of 500 major U.S. companies are expected to grow by 4 percent in revenue and 6 percent in earnings over the same period as compared to last year. Accepting the falls in their share prices as a warning from the market, not just a few companies are embarking on a bold restructuring for sustained growth.

The major information technology firm Hewlett-Packard has moved to split off its personal computer and printer businesses. Likewise, the major Internet auction firm eBay has decided to divest from PayPal, an online payment service provider. In the financial sector, Citigroup, desperately trying to emerge robust out of the ashes of the Lehman crisis, is retreating from consumer banking in Japan, Latin America, etc.

These [measures] are being undertaken as a restructuring to strengthen their core businesses; the feedback from the stock market is also favorable. Many Japanese companies, even after having lost competitiveness in their principal businesses, lack the decisiveness to make the right choices and then stick to them. On the other hand, U.S. companies, even in the midst of all the turbulence in the stock market, are solemnly undertaking reforms. If they are to compete with their U.S. counterparts in the global market, Japanese companies would do well to learn from such an attitude.