When oil prices rise sharply, it raises the cost of fuel and shrinks the amount of money consumers have to spend in the broader economy. But when the cost of crude falls too much, it weighs on growth in oil-producing nations.
Until recently, oil prices fell in a range between those two poles, according to UBS.
"However, now that we are getting closer to $100/bbl the net impact of higher oil prices is again becoming a net negative," UBS economists said in a research note. "The global sweet spot — where oil prices may have positively contributed to global growth — seems to be somewhere between $50/bbl and $70/bbl."
Oil prices at $100 a barrel would knock UBS' estimate for global growth in 2019 down from 4 percent to 3.86 percent. It says global inflation would top out at 4 percent if prices hit that level, up from the bank's current forecast for a 3.1 percent increase in consumer prices in July.
To be sure, those economic impacts would be felt very differently across the globe — UBS assessed the fallout for 15 different nations — but it certainly raises risks in the United States.
"We should take seriously the possibility of an oil price spike ... not least because oil spikes preceded 5 of the last 6 recessions (in the US)," UBS said.