The Fed figures on holdings for foreign official accounts showed a record week-over-week rise of $50.6 billion. Obviously Japan isn’t the only client represented in the group but agency holdings were virtually unchanged and US accounts were net sellers so there is a good reason to believe it was almost all USD/JPY buying.
Off the top of my head, that number seems a tad high. The Sept. 15, 2010 intervention was a reported $23.5 billion but it only yielded 300 pips vs teh 400 pips on Monday.
