A surge in the prices of shares in Japan¡¯s trading houses ¡ª triggered by a $6 billion investment by Warren Buffett ¡ª is already fading, due to a lack of fresh catalysts and a downturn in commodity markets.

Shares in two of the five s¨­g¨­ sh¨­sha, as the commodity-centric Japanese conglomerates are called, are now trading at or below levels before Buffett¡¯s Berkshire Hathaway Inc. announced its stake purchase.

The August announcement, among the largest investments ever made by Buffett in Japan, not only sparked a rally in stocks, but also boosted overall investor interest in the trading companies.