UPDATE 1-Brazil's Telefonica 4th-quarter profit down 57% but beats forecasts

(Adds more details on earnings report, context)

SAO PAULO, Feb 15 (Reuters) - Telefonica Brasil SA said on Wednesday its fourth-quarter net profit fell 57.2% from the year before, but still surpassed analysts' expectations due to an increase in the number of customers even as borrowing costs soared.

The telecommunications company, a unit of Spain's Telefonica SA, posted a 1.126 billion reais ($215.75 million) profit in the last three months of 2022, according to a securities filing, beating the 1.07 billion reais forecast by analysts in a Refinitiv poll.

Its bottom line was hit by a 604 million real expense in its financial result, as the company incurred more debt to help finance its acquisition of Oi SA's mobile arm last year, alongside TIM Brasil and America Movil's Claro.

Its total net debt at the end of December was 16.87 billion reais, compared to 10.44 billion reais a year earlier.

However, net revenues from Telefonica Brasil's mobile phone services, rose 13.6%, to 7.91 billion reais, boosted by the assets it inherited from Oi.

This month, Oi sought Chapter 15 bankruptcy protection, according to documents seen by Reuters, shortly after emerging from its first bankruptcy protection process in December after over six years shedding assets.

Recurring earnings before interest, taxes, depreciation and amortization (EBITDA) grew 6.1% to 5.23 billion reais.

In a separate filing, the firm said it plans to invest up to 9 billion reais this year. ($1 = 5.2190 reais) (Reporting by Carolina Pulice and Peter Frontini; editing by Jonathan Oatis and David Gregorio)