When it comes to the Bank of Japan's actions (or inactivity as case may be), traditionally the market's focus has been on whether or not Kuroda would expand QE and/or cut rates. However, while far less noticed, the central bank's aggressive purchases of ETFs are becoming a troubling reality. Recall that in April the BOJ was revealed to already be a top 10 holder in about 90% of all Japanese stocks. 

As Bloomberg reported, as of April the BOJ ranked as a top 10 holder in more than 200 of the Nikkei gauge's 225 companies. "The central bank effectively controls about 9 percent of Fast Retailing Co., the operator of Uniqlo stores, and nearly 5 percent of soy sauce maker Kikkoman Corp. It has an estimated shareholder rank of No. 3 in both Yamaha Corp., one of the world's largest makers of musical instruments, and Daiwa House Industry Co., Japan's biggest homebuilder."