The maintenance of a Buy rating suggests that Mizuho's outlook on WEC Energy Group remains positive, indicating an expectation of performance that will outpace the market or the analyst's sector benchmark. However, the reduction in the price target could reflect a slight tempering of growth expectations, possibly due to market conditions, regulatory factors, or company-specific events. This news is likely to have a neutral to mildly positive impact on the stock in the short term as it reaffirms investor confidence but also adjusts expectations.