Amazon’s Prime Day is slamming into President Donald Trump’s trade war, with ever-shifting tariffs prompting some brands to sit out the summer sale and some shoppers dropping hints they plan to pull back.

A record $23.8 billion in sales is expected to be spent by consumers for Amazon Prime Days, Adobe said in a forecast released on July 7. That's a 28.4% increase year over year and $9.6 billion more than the comparable period last year. Last year, shoppers spent $14.2 billion during the two-day Amazon Prime event, according to Adobe.

Prime Day sales are here again. The e-commerce giant is making the now-misnamed Prime Day a four-day event for the first time.