US dollar index, 1 week chart. Markets Insider The dollar has weakened to a four-month low.

The US dollar index is down by 0.6% at 99.02 as of 8:06 a.m. ET. The last time it was at this level was in mid-November.

The index is down by about 3% since the start of 2017.

"Although there are conflicting impulses, interest rate differentials continue to appear to be the single most important factor in considering currency movement presently," Marc Chandler, the global head of currency strategy at Brown Brothers Harriman, wrote. "The question of the dollar is in good measure a question of the direction of interest rates."

Separately, Dallas Fed manufacturing will be out at 10:30 a.m. ET.

As for the rest of the world, here's the scoreboard as of 7:51 a.m. ET: