SAO PAULO (Reuters) - Brazilian financial technology start-up Nubank now has 15 million clients, the firm’s chief executive said on Friday, a figure which underlines the rapid growth of the Sequoia Capital-backed venture in Latin America’s largest economy.

FILE PHOTO: The logo of Nubank, a Brazilian FinTech startup, is pictured at the bank's headquarters in Sao Paulo, Brazil June 19, 2018. REUTERS/Paulo Whitaker

Nubank founder and CEO David Vélez disclosed the figure, which marks a 25% increase from the total it revealed in August, at the Brazil Investment Forum in Sao Paulo.

Nubank, which also operates in Argentina and Mexico, has become a household name in parts of Brazil through its purple, free-of-charge credit card. The company, whose investors also include China's Tencent Holdings Ltd 0700.HK, offers digital savings accounts and personal loans.

In late July, the firm raised $400 million in a funding round led by U.S. investment firm TCV. The Wall Street Journal reported at the time that the company, which was founded in 2013, was valued at more than $10 billion.

Vélez said that 10 million out of the 15 million clients are holders of the bank’s credit card.

“We have opened many new business fronts in the last 12 months. We are growing quickly,” he said.

The fintech, which started only as a supplier of the fee-free credit card, has expanded into bank account offerings, services for small businesses and, more recently, to credit lines to individuals.

Vélez said the bank aims to offer interest rates direct credit to consumers that are 30% to 40% lower than normal rates in the Brazilian banking market.

The executive said Nubank would push in coming weeks to accelerate its offerings in Mexico.

(This corrected story changes, in paragraph three, the color of card marketed by Nubank to purple from green)