Both candidates have said they cannot envisage defeat in the run-off, paving the way for a possible dispute when results come in on Monday or Tuesday, and a possible resumption of street protests. There are more than five million registered voters.
Samir Gadio, London-based emerging markets analyst at Standard Bank, said the market had been negative on Senegal's $500 million Eurobond before the first round vote due to the deteriorating political and security climate.
"The smooth electoral process since and the possibility of an orderly transition in coming days would boost Senegal's historical reputation of political stability," Gadio said in a note, adding this sentiment was now shifting short-term risks to the bond's yield outlook to the downside.
"The main stress point is obviously whether both parties will immediately accept the outcome of Sunday's contest," he said.