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Analyst sees warning flags fly over MercadoLibre

MercadoLibre, the eBay and Amazon.com of Latin America, has been a monster stock since its IPO in 2007.

Along the way, founder and CEO Marcos Galperin has sold shares a number of times, and in a few instances the stock fell shortly afterward.

His well-timed sales are why George Muzea of Muzea InsiderConsulting calls Galperin a good insider—someone whose sales are worth watching—and why he warns, "He has top-ticked before. Be careful."

And as I wrote on TheStreet.com, Galperin's latest sales of 293,338 shares coincide with plunging currency and inflation in both Venezuela and Brazil—and with accusations by consultant Mark Roberts of Off Wall Street that MercadoLibre's forex accounting leads to propped-up results.

In a nutshell, Roberts says the forex accounting artificially inflates sales and earnings (he went into more detail in an article here)—an assertion the company disputes.

"We do not comment on conjectural interpretations of our financial results," said a MercadoLibre spokesperson. The company did not respond to my inquiries about Galperin's stock sales.

CNBC Contributor HerbGreenberg is a commentator at TheStreet.com and editor of Herb Greenberg'sReality Check. Follow him on Twitter:@herbgreenberg and Google

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