The IBEX 35 opened virtually flat on Tuesday, as optimism over corporate earnings set to be released by major companies throughout the week was offset by nervousness over the international political landscape and the unpredictability of the United States' trade agenda.

Caution increased after President Donald Trump stated that he would raise tariffs imposed by the United States on imports of goods from South Korea to 25%, citing an alleged breach of the trade agreement with Washington. 

For now, investors are watching these frictions while awaiting further corporate results and the Federal Reserve's decision, scheduled for Wednesday. No changes in interest rates are expected, but the market will be closely watching for signals regarding the direction of monetary policy, with expectations for at least two rate cuts this year.

This week will see earnings reports from Texas Instruments, UnitedHealth, Boeing, and General Motors (Tuesday); ASML, IBM, Meta, Microsoft, Tesla, and AT&T (Wednesday); STMicroelectronics, Deutsche Bank, ING, and Apple (Thursday); and CaixaBank (Friday).

In the background, tensions persist in the United States following the fatal shooting of a second American citizen by federal immigration agents in Minnesota.

On Tuesday's macroeconomic agenda, the main reference will be the Conference Board's consumer confidence index in the US.

Against this backdrop, at 08:05 GMT on Tuesday, Spain's IBEX 35 index was up 4.70 points, or 0.03%, at 17,685.20 points, while the FTSE Eurofirst 300 index of leading European shares advanced 0.31%.

In the banking sector, Santander rose 0.34%, BBVA gained 0.19%, CaixaBank advanced 0.42%, Sabadell climbed 0.77%, Bankinter was up 0.59%, and Unicaja Banco increased 0.92%.

Among the major non-financial stocks, Telefónica fell 0.98%, Inditex dropped 0.70%, Iberdrola slipped 0.13%, Cellnex declined 0.96%, and Repsol lost 0.56%.

(Reporting by Tomás Cobos, editing by Jorge Ollero Castela)