Unlikely that negative rates will be implemented in the U.S. any time soon, hurdle remains high.
But the case for them has strengthened.
Skeptical that forward guidance and asset purchases can fill the gap, barring a dramatic foray into risky assets for which the Treasury (and ultimately Congress) would need to provide a lot more equity capital.
The news seems to have offered additional strength to the US dollar and also favored risk-tone. That said, the USD/JPY takes the bids to 107.78 whereas S&P 500 Futures reverse the early-day losses to -0.02% by the press time of the initial Asian session on Wednesday.