The automakers will report May vehicle sales on Thursday, June 1st.
Note: There were 25 selling days in May 2017, up from 24 in May 2016.
From Reuters: U.S. auto sales seen up 0.5 percent in May: JD Power and LMC
U.S. auto sales in May will edge up 0.5 percent from a year earlier, despite consumer discounts remaining at record levels, industry consultants J.D. Power and LMC Automotive said on Thursday.
…
The seasonally adjusted annual rate for the month will be 16.9 million vehicles, down from 17.3 million last year. …The consultancies cut new vehicle sales forecast for 2017 to 17.2 million units from 17.5 million units. U.S. sales of new cars and trucks hit a record high of 17.55 million units in 2016. But as the market has begun to saturate, automakers have been hiking incentives to entice consumers to buy.
emphasis added
Overall sales are mostly moving sideways (and down a little from the record in 2016).