https://www.gamespot.com/articles/nintendo-switch-outsells-ps4-xbox-one-in-us-august/1100-6453355/

The NPD Group today released its monthly report for August 2017 sales in the United States, and on the hardware front, the Nintendo Switch took the cake. Nintendo's hybrid console was the best-selling system in the US during the month. The Switch has been the best-selling system in four of the six months since launch in March, only beaten by the PlayStation 4 in May and June.

On a year-to-date basis, the PS4 remains the best-selling console in the US, according to NPD data. The group does not release specific sales numbers, so we don't know how substantial Nintendo's margin of victory this month.