(Bloomberg) -- The Treasury yield curve reached its steepest level in four years as risk appetite improved amid signs that negotiators from the U.K. and the European Union are drawing close to a post-Brexit trade deal.

The gap between 5- and 30-year yields expanded on Wednesday to its widest since November 2016 as investors sold long-term debt and stocks climbed given the potential for reduced trade tension and a brighter outlook for the global economy. The sustainability of the move in rates remains a wildcard given uncertainty over the U.S. stimulus package, after President Donald Trump demanded changes.

Short-term rates held mostly steady given the Federal Reserve has made clear that it won’t lift its policy rates for years. Longer-term yields, however, climbed with the 10-year nearing the psychological 1% mark it hasn’t reached since March. Some signs of improvement in the U.S. labor market also helped lift the 10-year yield, to as high as 0.966%.

“This morning’s U.S. data offered just enough good news to allow rates to rise on word Brexit negotiations could produce a deal announcement today or tomorrow,” Jim Vogel, who manages fixed-income strategy at FHN Financial, said in a note.

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