Warren Buffett can cause executives angst when he invests in their companies.

Japan’s trading firms illustrate this point. Berkshire Hathaway bought stakes in them in August 2020, which raised their international profile and attracted other investors. Over the next four years, the five companies outperformed the broader market.

Buffett’s influence can cut both ways however. When Berkshire Hathaway pared its stake in Taiwan Semiconductor Manufacturing Co. last year because of geopolitical risk, the chipmaker’s shares quickly dropped as other investors followed in his wake. With that example in mind, Japan’s trading companies are now taking steps to try and mitigate the impact if Buffett ever decides to sell.