By Dave Sherwood and Antonio De la Jara
SANTIAGO (Reuters) - Chile's presidential hopefuls were to wrap up campaigning on Thursday, three days ahead of a tight runoff election whose outcome will determine whether the world's top copper producer will turn to the right or maintain its center-left track.
Voters on Sunday will choose between billionaire conservative Sebastian Pinera and center-left senator and journalist Alejandro Guillier. During the November first-round election, a surprise surge by harder leftists confounded pollsters, sent markets plummeting and set the stage for a tighter-than-expected runoff.
"Everything points to a narrow margin of victory," said Guillermo Holzmann, a professor at the University of Valparaiso. "It's an unusual race in that it's been difficult to gauge the electorate."
There have been no major polls since the Nov. 19 first round.
Both Pinera and Guillier would keep in place the longstanding free-market economic model in Latin America's most developed country. But candidates with more extreme views on both the right and left performed better than expected in November, leading both men to make concessions to try to win over voters whose first-round choice dropped out.
Pinera, 68, a former president and the market favorite, placed first with 36.6 percent of the vote in the first round. He has vowed to boost growth by cutting the corporate tax rate and scaling back outgoing President Michelle Bachelet's tax, labor and education reforms that Guillier has vowed to deepen. [L1N1O620J]
The bearded Guillier, 64, a center-left senator from northern Chile, garnered 22.7 percent of the vote in November from backers hoping to preserve gains made in Bachelet's government for students, women and workers, measures such as lower university fees and laws empowering unions.
Guillier narrowly edged out third place finisher Beatriz Sanchez of the leftist Frente Amplio. She received support from 20 percent of voters with promises to tax the "super-rich" to boost social spending and fight inequality.
Sanchez's 1.3 million voters are seen as pivotal in the upcoming election. Voting is voluntary in Chile, and abstention has run high in recent years.
"It comes down to how many people stay home - and particularly, how many people stay home on Guillier's side," said University of Chile professor Robert Funk.
Guillier has courted leftists by proposing to overhaul the country's privatized pension system and rewrite its constitution. Pinera has sought to appeal to centrist voters by calling for free technical education for the poor and a public pension option.
Both candidates were to make final televised appearances Thursday evening just blocks away from each other in the Chilean capital.
(Reporting by Dave Sherwood; Editing by David Gregorio)