The company posted a profit of $359.0 million for the July-September period, while analysts polled by LSEG expected $298.1 million.

"We had another super solid quarter," Andre Chaves, senior vice president of strategy and corporate development, told journalists, highlighting the acceleration of revenue growth in e-commerce and the firm's fintech arm in its major markets.

Adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) grew 108.7% to $820 million. Its operating margin stood at 18.2% in the period, compared to 16.3% in the second quarter and 11% a year earlier.

Total net revenue was around $3.8 billion in the quarter ended in September, up 39.8% year-on-year.

Analysts had expected adjusted EBITDA of $636.5 million and revenue of $3.6 billion.

Margin growth was driven by the marketplace, said Chaves, attributing the movement to the increase in revenue and efficiency gains in logistics and expenses.

"All cost lines are growing, but the business is growing much faster and costs are growing in a disciplined manner."

Within the e-commerce operation, net revenue rose to $2.1 billion, up 45.2%.

"Brazil was the star of the quarter," said Chaves.

The country's share of marketplace revenues rose from around 53% to almost 57% from the year-ago period, but revenue from Mexico and Argentina also grew.

In its financial services arm, Mercado Pago, net revenue grew 33.2% to $1.6 billion, as the company increased the pace of lending, while its total volume of payments processed also jumped.

(Reporting by Andre Romani; Writing by Peter Frontini; Editing by Kylie Madry)