If imitation is the sincerest form of flattery, Amazon.com Inc. must feel flattered today.

Amazon, No. 1 in the Internet Retailer 2016 Top 500 Guide, is holding its second annual Prime Day promotion today, offering steep discounts on hundreds of thousands of items to Prime members, who pay a $99 annual subscription fee for such perks as unlimited expedited shipping.

Many other major retailers launched their own online sales to grab some share of consumers’ heightened interest in e-commerce on Prime Day—and for good reason. In 2015, the first year Amazon held Prime Day, that date (July 15) was the fourth-busiest day for the top 25 online retailers last year in terms of web traffic. In addition to Amazon, 23 of the 50 largest retailers in the 2016 Top 500 are running some sort of promotion today. Here is what they are offering:

• Dell Inc. (No. 3) is running a Black Friday in July promotion. The company is offering up to 67% off such products as personal computers and servers online. The sale started at 10 a.m. Central Tuesday.
• Wal-Mart Stores Inc. (No. 4) started cutting prices on thousands of items last week and is offering free shipping with no minimum purchase on online orders Monday through Friday. Its usual free shipping threshold is $50. The retail chain is also offering a free 30-day trial of its Amazon Prime-like ShippingPass program. Normally, customers would have to pay a $49 annual fee in exchange for perks such as free two-day shipping and returns on select items. SimilarWeb’s data showed Wal-Mart posted a 61.9% overall traffic spike compared to its daily average on Prime Day last year, better than Amazon’s 44.9% traffic spike and tops among all major retailers.
• Macy’s Inc. (No. 6) is holding its first Black Friday in July promotion. The retail chain is offering discounts on nearly 32,000 items online only and free shipping with no minimum purchase to U.S. shoppers until midnight Pacific. Macy’s also will expand the sale to include items online and in stores Wednesday through Sunday. SimilarWeb’s data shows that Macy’s posted an 81.4% spike in traffic on mobile devices on Prime Day last year and a 58.4% traffic spike overall.
• Office Depot Inc. (No. 9) is holding a one-day, online-only flash sale, offering discounts of more than 60% on select items.
• QVC Group (No. 10) designated Tuesday as Easy Pay Day. The television and online retailer is offering discounts on more than 250 items online through 11:59 pm Pacific. Shoppers can pay for the items using QVC’s Easy Pay service, which allows shoppers to receive an item now and pay for it in installments.
• Best Buy Co. Inc. (No. 12) is running a promotion on its website specifying “Deals for all. No membership needed,” a not-so-veiled shot at Amazon, offering discounts on an assortment of electronics. Last year, Best Buy saw a 27.0% traffic spike on Prime Day last year over its daily average, fifth among all major retailers, according to SimilarWeb.
• Online-only electronics retailer Newegg Inc. (No. 17) is running its second annual FantasTech 24-hour sale today. The retailer is adding new deals across hundreds of product categories throughout the day, similar to Amazon. According to SimilarWeb, Newegg saw a 39.2% traffic spike over its daily average on Prime Day last year, fourth among all major retailers.
• Kohl’s Corp. (No. 19) began running a string of daily deals online starting Sunday and continuing through Thursday. Discounts are on apparel, electronics  household items and more.
• Gap Inc. (No. 20) is offering up to 60% off select items both online and in-store during a 48-hour sale, but a spokeswoman would not comment about the sale’s timing or Prime Day.
• Williams-Sonoma Inc. (No. 21) is offering free shipping on all online orders with no minimum through 11:59 pm Eastern Tuesday.
• Groupon Goods (No. 26) is offering an extra 10% off up to three Groupon Goods deals through Wednesday.
• Lowe’s Cos. Inc. (No. 27) is offering free shipping on all online orders of $19 or more on Tuesday only.
• Vistaprint (No. 31) is holding its semi-annual sale, offering up to 50% off select items.
• J.C. Penney Co. Inc. (No. 33) is holding a sale dubbed “Penney Palooza,” which started Monday and runs through the end of Tuesday, offering shoppers an additional 25% off all items and free shipping on online orders over $49.
• L.L. Bean Inc. (No. 34) is running a summer sale, offering up to 60% off select items.
• Toys ‘R’ Us Inc. (No. 35) is offering 15% off regular-priced items on ToysRUs.com and BabiesRUs.com all day Tuesday.
• Fanatics Inc. (No. 38) is running its “biggest clearance event of the year,” offering up to 70% off select items through Wednesday at 5 p.m. Eastern and free shipping on purchases of $40 or more.
• HP Home & Home Office Store (No. 40) is offering limited offers on select items. It says  new deals are showing up every day on items including PCs, keyboards and headphones.
• Lands’ End (No. 44) is offering 30% off shirts and tops on Tuesday only.
• GameStop Corp. (No. 45) is offering free two-day shipping on online orders over $50 on Tuesday only.
• Shutterfly Inc. (No. 46) is running a 72-hour sale Monday through Wednesday offering 50% off orders of $99 or more, 40% off orders of $49 or more and 30% off orders under $49.
• J.Crew Group Inc. (No. 49) is running a 48-hour sale that started Monday and ends today, offering shoppers an additional 50% off final sale styles online and in store.
• Online-only electronics retailer TigerDirect (formerly owned by No. 32 Systemax Inc.) is offering a 24-hour sale promising that shoppers can “save big without paying annual fees.”
• EBay Inc. also decided to get in on the action, stressing on its site “no membership required” to take advantage of the deals it is offering, including up to 70% off certain items.

Want a quick fact sheet on Amazon Prime Day from 2015 and how it compared to all other major e-retailing sale events?