BUENOS AIRES (Reuters) - Former Argentina President Cristina Fernandez narrowly won an Aug. 13 primary vote for a Senate seat in Buenos Aires province by 0.2 percentage points, National Electoral Director Fernando Alvarez said on local radio on Tuesday.

Cristina Fernandez de Kirchner, former Argentine President and candidate for the Senate in the mid-term primary elections, greets supporters at her campaign headquarters in Buenos Aires, Argentina early August 14, 2017. REUTERS/Marcos Brindicci

The electoral authority last updated the count with 95.68 percent of polling stations reporting on Aug. 14, showing President Mauricio Macri’s ally Esteban Bullrich ahead by 0.08 percentage points in a technical tie in the nation’s largest province.

“It’s a very small difference, a minimal difference, a difference without precedent,” Alvarez said on Radio Mitre, explaining only around 20,000 votes separated the two.

Stocks rallied and the peso strengthened after the Aug. 14 count as fears eased that the populist Fernandez could be aiming for a presidential comeback in 2019 and reverse Macri’s economic reforms.

The election will occur on Oct. 22, and markets are unlikely to be fazed by the primary result as Fernandez had originally been expected to win by an even wider margin.

Fernandez claimed victory over Bullrich, Macri’s former education minister, in the primary at a 4 a.m. rally on Aug. 14, and her party has accused the government of manipulating the count to favor Macri’s candidates.

Alvarez said the tally had occurred at a normal place.

Traders had priced in a Fernandez primary win by a margin of around 3 percentage points, according to J.P. Morgan. Local brokerage Portfolio Personal had said the market expected her to win by between 2 and 4 percentage points.

Fernandez was president from 2007 to 2015 and was indicted for corruption last year.

Under Argentina’s election system, the winning party in each Senate race gets two of the province’s three seats, with the remaining seat going to the second-place finisher.

A second-place finish in October would therefore still grant Fernandez, 64, a seat, which would give her immunity from arrest though not from trial. She dismisses the corruption accusations as politically motivated.

No matter how many seats his “Let’s Change” coalition picks up in October - when Argentines elect one-third of the Senate and half the lower house of Congress - Macri will still lack a majority. He must build alliances to pass reforms, but analysts said a defeat for Fernandez would strengthen his negotiating position.