OLIVIER DOULIERY/Getty ImagesThe latest inflation data has bolstered the case for looser monetary policy.Investors cheered a soft May inflation report, which could pave the way for Fed easing this year.Rate cuts in September are "overwhelmingly likely," one economist said.Wall Street is feeling a lot more upbeat on the path of interest rates this year.On Wednesday, investors cheered a positive report on the consumer price index for May.