Amazon.com’s Prime Day has become a major marketing opportunity and shopping event in the annual calendar for other U.S. retail companies.

Amazon’s sales are pushing other retailers to respond as they seek to remain competitive.

Walmart Inc, Target Corp and eBay Inc all run their own special promotions to coincide with the annual sale, which this year Amazon has stretched to two days.

Target announced deal days which will run on the same days as Prime Day - July 15 and 16. Walmart offered promotions from July 14th-17th, while eBay announced a July 15 “crash sale.”

Amazon customers have to join Amazon Prime to get discounts during the 48-hour event. U.S. members of the club pay $119 per year for benefits including one-day shipping, and they tend to buy more goods, more often from Amazon.