EMERGING MARKETS-Latam stocks sink on Peru vote; US growth fears

* Peru stocks tumble on leftist Humala's election win

* Grupo Mexico slump drives Mexico's IPC to 8-month low

* Brazil down 1.98 pct, Mexico's IPC off 1.28 pct

SAO PAULO, June 6 (Reuters) - Latin American stocks fell on Monday as Peru's market tumbled by the most on record as investors reacted to the election of leftwing former army commander Ollanta Humala, while concerns of slowing U.S. growth weighed across the region.

The MSCI Latin American index .MILA00000PUS shed 2.2 percent, its worst one-day percentage loss in a month.

Peruvian stocks .IGRA fell 12.45 percent, their worst one-day percentage drop ever, and trading was suspended early, leaving stocks at their lowest levels in more than a month. With most voting results in, Humala claimed victory following a bitter presidential race. [ID:nN06237167]

Investors worry Humala, who has vowed the poor will share in the country's new wealth, will increase state control over the economy and throw away fiscal discipline.

Humala said he will emulate moderate leftists like Brazil's former President Luiz Inacio Lula da Silva. But some investors fear he could follow policies more in the vein of Venezuela's Hugo Chavez.

"There will be that suspicion until he proves he's more like Lula than Chavez," said Newton Rosa, chief economist with SulAmerica in Sao Paulo.

Mining stocks were hit particularly hard in Peru and elsewhere, as investors fretted over the prospect of a windfall tax Humala wants to impose on Peru's vast mining sector.

Mexican mining company Grupo Mexico (GMEXICOB.MX), which owns mines in Peru, slumped 7.47 percent in its worst one-day drop in more than two years.

Bank of America Merrill Lynch analysts on Monday downgraded shares of Grupo Mexico and its Peruvian unit Southern Copper (SCCO.K)(SOUi.LM) to neutral. [ID:nN06145689]

Grupo Mexico's losses helped drag Mexico's IPC stock index .MXX down 1.28 percent through a key support level and down its lowest since October 2010.

Also weighing on sentiment in the region, U.S. stocks fell for a fourth straight day as a spate of recent weak U.S. data reinforced concerns that growth in the United States is slowing.

Brazil's benchmark Bovespa stock index .BVSP fell 1.98 percent.

Investors are also wary of an acrimonious political scandal that has embroiled the Brazilian president's chief of staff, Antonio Paloccai, said Andre Luis Querne, a partner at asset management firm Rio Gestao de Recursos. [ID:nN03162154]

Palocci, a former finance minister and an influential supporter of fiscal discipline, is facing growing pressure to explain more fully a surge in his personal wealth while he served as a lawmaker from 2007-2010.

Should Antonio Palocci leave office, Querne said, "it could be a positive in the sense of the government trying to take care of a problem, but it could depend on the way it unfolds politically."

The scandal adds to policy uncertainty in Latin America's biggest economy as inflation, already above target, threatens to stay high through the end of the year.

Among stocks falling in Brazil were energy companies, with preferred shares of state-controlled energy company Petrobras (PETR4.SA) down 2.44 percent and OGX (OGXP3.SA) down 3.8 percent.

Banks also fell. Itau Unibanco (ITUB4.SA), the country's largest private-sector bank by assets, dropped 2.32 percent.

The central bank is expected to hike its benchmark interest rate to 12.25 percent from 12 percent at a Wednesday meeting as it seeks to coax inflation back toward target. [ID:nE5E7GR00V]

The government could also use other measures to clamp down on banks by restricting the amount of credit they offer.

Hanging over banking stocks, said Pedro Galdi, an analyst at SLW brokerage, "you have these government questions, with the possibility of more macroprudential measures."

Chile's IPSA index .IPSA fell 1.36 percent as companies with operations in Peru sank.

Shares of top Chilean retailer Falabella FAL.SN fell 2.3 percent while the country's top airline LAN LAN.SN sank 2.73 percent. (Reporting by Luciana Lopez and Aluisio Pereira in Sao Paulo and Michael O'Boyle in Mexico City; Editing by Dan Grebler)