Following yesterday's Yen surge in the aftermath of the disappointing BOJ announcement, the pain for USDJPY long continued, with the key carry pair tumbling as low as 106, the lowest level since October 2014 before stabilizing around 107, and is now headed for its biggest weekly gain since 2008, which in turn has pushed the US dollar to to its lowest close in almost a year as signs of slowing growth in the U.S. dimmed prospects for a Federal Reserve interest-rate increase. As a result, global stocks fell and commodities extended gains in their best month since 2010.

The yen strengthened against all 16 major peers for the second day in a row, climbing as much as 1.1 percent to 106.91 a dollar, the strongest level since October 2014. It surged 4.3 percent this week as the Bank of Japan defied economists' expectations that stimulus would be stepped up.

The sliding dollar is proving beneficial for raw materials, helping lift gold and silver to 15-month highs. Crude oil has jumped 21 percent this month to more than $46 a barrel in New York. European equities trimmed their biggest monthly advance since November.

As Bloomberg writes, the dollar's third straight monthly drop and the prospects for the Fed moving gradually on interest rates are spurring the outlook for inflation, with the 10-year U.S. break-even rate at the highest since July. Reports today on consumer confidence and personal spending will provide clues on the trajectory of the world's largest economy after data on Thursday showed the slowest pace of expansion in two years.