Market shifts.

Tired--or scared--of the high prices and wafer-thin yields on Japanese government bonds (JGBs), investors have begun selling. Investors bought ¥3 trillion of foreign bonds in April, and ¥3.7 trillion in May, the most--bar one freak month--on record. Besides investing in Treasury bonds, insurers have been buying the paper of American quasi-governmental agencies. Japan's wretched investment environment is also pushing regional banks to break with tradition and move money into foreign bonds. That will be one reason why the Bank of Japan, which already buys ¥1.2 trillion-worth of bonds each month as a way of pumping money into the economy, will not want to let the market slip too far.