The Bank of Japan's decision last week to expand the scope of its asset purchase program not only seemed to disappoint the market by apparently exposing the limitations of its monetary stimulus but also effectively represented the central bank's attempt to intervene in the management decisions of private-sector firms through monetary policy.

In expanding its annual purchase of exchange-traded funds (ETF) by around ¥300 billion from the current pace of about ¥3 trillion beginning in April, the BOJ said it would buy ETFs composed of stocks issued by companies that are "proactively making investments in physical and human capital." The new policy resonates with the repeated calls by the administration of Prime Minister Shinzo Abe on businesses to spend more of their increased profits on wage hikes and capital investments to shore up the economy.

BOJ Gov. Haruhiko Kuroda said the bank will extend as much support as it can to encourage companies to make the investments and raise the wages of their workers. Kuroda said the annual spring wage negotiations between the management and labor unions at major firms "influence consumer spending and price trends" and that the BOJ is "strongly interested" in the outcome of the talks in its bid to achieve a 2 percent annual inflation target — a commitment that he made when he launched the monetary stimulus to end deflation.