Shares of BBVA Banco Frances SA (BBAR) tumbled 5.43% in pre-market trading on Thursday, following the release of the company's second-quarter earnings report. The significant drop comes as the South American lender reported a year-over-year decline in both earnings and net interest income, disappointing investors.

According to the report released late Wednesday, BBVA Banco Frances SA's Q2 earnings came in at 271 Argentine pesos ($0.21) per American depository share, marking a substantial decrease from 544 pesos in the same period last year. While this figure surpassed the FactSet analyst consensus of 204.36 pesos, the year-over-year decline has clearly rattled investors.

Adding to the negative sentiment, the bank's net interest income for the quarter ended June 30 fell to 591.81 billion pesos, down from 946.05 billion pesos a year earlier. This decline in a key profitability metric for banks has likely contributed to the sharp pre-market sell-off. The pre-market plunge of 5.43% indicates that investors are reassessing the bank's near-term prospects in light of these results, despite the earnings beat against analyst expectations.