Although markets rate the possibility of a 25 basis point hike in July at 92.4%, it is possible that the report will help determine how many more hikes are in the pipeline.
Economists polled by Reuters estimate the consumer price index to have risen 3.1% in June, following May's 4% increase. The underlying index would have fallen for the third consecutive month from 5.3% to 5%. This is still more than double the Fed's 2% target.
According to economists at ING, the underlying index would have to come in well below forecasts for a rate hike in July to look doubtful.
"We don't think that's going to happen," they noted.
Against this backdrop, at 07:05 GMT on Wednesday, Spain's selective Ibex-35 stock market index was up 23.30 points, or 0.25%, to 9,354.40 points, while the FTSE Eurofirst 300 index of large European stocks was up 0.31%.
The energy company Naturgy opened at the top of the index with a rise of 1.86% after announcing that it has revised its annual dividend floor and targets for 2025.
In the banking sector, Santander rose 0.82%, BBVA gained 0.40%, Caixabank advanced 0.32%, Sabadell gained 1.08%, Bankinter gained 1.19%, and Unicaja Banco rose 0.41%.
Among the large non-financial stocks, Telefónica gained 0.47%, Inditex advanced 0.44%, Iberdrola gained 0.18%, Cellnex fell 0.22%, and the oil company Repsol lost 0.08%.
(Reporting by Flora Gómez; additional information by Ankur Banerjee; edited by Tomás Cobos)