Spain's IBEX 35 stock index opened higher on Wednesday, extending its winning streak to a fourth session, awaiting the release of U.S. inflation data, which could set the tone for the Federal Reserve's September meeting.

According to data released the day before, producer prices in the US rose less than expected in July, as the rise in the cost of goods was tempered by cheaper services, indicating that inflation continued to moderate.

Slowing inflation and a cooling labor market have led financial markets to anticipate that the Federal Reserve will begin its easing cycle in September.

However, investors will be closely watching the release of the July US consumer price data at 1230 GMT, where they expect 0.2% increases in both the headline and core indexes, with the core index slowing to 3.2% on a yearly basis.

The data "should set the tone for the market ahead of expectations of rate cuts (the market assigns a 54.5% probability of a -50 bps cut at the next meeting in September)," said Renta 4 in a note to clients.

"Both repeating and slightly loosening would be good results for (the) stock markets," Bankinter analysts added on Telegram.

The day will also see the release of second-quarter eurozone GDP (0900 GMT).

Before markets opened, the U.K. reported that consumer price inflation rose to 2.2% after two months at the Bank of England's 2% target, a slightly lower increase than economists expected.

At 0702 GMT on Wednesday, Spain's selective IBEX 35 stock market index was up 39.60 points, or 0.37%, to 10,763.40 points, while the FTSE Eurofirst 300 index of large European stocks was up 0.34%.

In the banking sector, Santander rose 0.44%, BBVA gained 0.22%, Caixabank advanced 0.60%, Sabadell gained 0.17%, Bankinter gained 0.24%, and Unicaja Banco rose 0.52%.

Among the large non-financial stocks, Telefónica gained 0.12%, Inditex advanced 0.14%, Iberdrola gained 0.08%, Cellnex gained 0.64%, and the oil company Repsol rose 0.55%.

(Information by Benjamín Mejías Valencia; edited by Mireia Merino)