(Recasts with Guillier conceding)
SANTIAGO, Dec 17 (Reuters) - Billionaire conservative Sebastian Pinera won Chile's presidency on Sunday, with his center-left opponent Alejandro Guillier conceding the election as Chile followed other South American nations in a political turn to the right.
With 98.44 percent of the ballots counted, Pinera, 68, had won 54.57 percent in the run-off vote, to 45.43 percent for senator Guillier, a wider than expected margin in a race that pollsters had predicted would be tight.
Months of campaigning exposed deepening rifts among the country's once bedrock center-left, an opening former president Pinera leveraged to rally more centrist voters around his proposals to cut corporate taxes, double economic growth and eliminate poverty in the world's top copper producer.
In his concession speech at a hotel in downtown Santiago, Guillier called his loss a "harsh defeat" and urged his supporters to defend the progressive reforms of outgoing President Michelle Bachelet's second term.
Many Chileans had viewed the election as a referendum on her policies, which focused on reducing inequality by making education more affordable and overhauling the tax code.
Pinera's supporters cheered the news at his campaign headquarters as the results were swiftly tabulated on a hot and sunny Santiago evening.
Though neither candidate would have marked a dramatic shift from Chile's long-standing free-market economic model, a Pinera victory underscores an increasing tilt to the right in South America following the rise of conservative leaders in Peru, Argentina and Brazil.
Pinera painted Guillier, a former TV anchorman and current senator, as extreme in a country known for its moderation, and likened him to Venezuela socialist President Nicolas Maduro.
But Pinera's own conservative agenda may also struggle, at a time when efforts by his ideological allies in Brazil and Argentina to reduce fiscal deficits by cutting spending have faced political opposition and sparked protests.
The investor favorite, Pinera's proposals are seen as miner-friendly in a country where copper is king. He has pledged support and stable funding for Chile's state-run miner Codelco , and has promised to slash red tape which had bogged down projects under Bachelet.
After a leftist party made unexpected gains in November's first round, Pinera sought to woo less well-off voters with proposals such as the creation of a public pension fund to compete with Chile's much-criticized private pension funds, and the expansion of free education.
The race marks a turning point for Chile's historic coalition of center-left parties, previously known as the Concertacion. The pact fissured under Bachelet, riven by disagreements over policies such as loosening Chile's strict abortion laws and strengthening unions.
Pinera seized on the backlash, campaigning on a platform of scaling back and "perfecting" her tax and labor laws, seen by many in the business community as crimping investment at a time slumping copper prices were weighing on the economy.
"I voted for Pinera because I am an entrepreneur. I value my own efforts and do not expect much from the government," said Rosario Poma, 53. "I think (Pinera) will be good for investment."
(Additional reporting by Felipe Iturrieta and Caroline Stauffer; Writing by Caroline Stauffer; Editing by Jeffrey Benkoe and Rosalba O'Brien)