Marketplace Briefing: This year’s 4-day Prime Day is a ‘winner-takes-all’ test for Amazon sellers

The format change is reshaping how brands prepare for the high-stakes event, especially amid continued uncertainty around tariffs, rising costs and shifting consumer demand. For some sellers, the four-day stretch opens new opportunities to capture market share. For others, the extra days add logistical headaches and amplify risk. As one brand founder put it, Prime Day 2025 is shaping up to be a “winner-takes-all” event, where the brands with pricing power, operational agility and sharp strategy stand to dominate.

“You’re going to see fewer deals overall, but the brands that do participate in deals will be the bigger winners,” said Dave Dama, CEO of oral-care brand AquaSonic.

That sentiment isn’t shared by everyone. As Modern Retail previously reported, tariffs remain one of the biggest obstacles for online merchants this year. Many brands that manufacture in China were rattled after the steepest duties spiked as high as 145%. Some dropped out of Prime Day altogether, with others planning to offer fewer discounts. Even after tariffs on Chinese imports were lowered to 30%, many scrambled to bring in inventory in time for Prime Day, with Amazon’s earlier-than-usual Prime Day deadlines exacerbating the crunch. For hard-hit brands moving forward with Prime Day, the strategy is more cautious: tweaking ad spend or offering more selective deals.

For AquaSonic, which manufactures many of its products in Vietnam, the tariff-induced disruption has become an opportunity. The brand ordered additional containers in anticipation of diminished competition and will offer deep discounts of as much as 60% on top sellers. AquaSonic, which saw a 300% year-over-year increase in sales during last year’s Prime Day and moved over 80,000 units over the course of the two-day event, is expecting record-breaking sales this year.

“Brands that have supply chains based elsewhere, and not just in China, are in a position to take a bigger lion’s share of the sales this year,” Dama said.

High-stakes prep

Flaus, a direct-to-consumer dental tech company, is taking a similar approach. The brand only runs sales twice a year — once on Prime Day, and again during Black Friday — and its founder and CEO, Samantha Coxe, sees this July’s event as a critical moment for growth. Amazon is the company’s only wholesale partner and accounts for about 25% of the brand’s revenue. 

“We’re full steam ahead,” said Coxe. “We were considering skipping Prime Day entirely because of tariffs, but once the rate dropped to 30%, we moved quickly to get inventory in.” Flaus imported five months’ worth of inventory ahead of Prime Day. 

Typically, Flaus has eight to 10 weeks of inventory on hand, but when the duty rate on Chinese imports fell, the company rushed to order five months’ worth of inventory. Coxe said this was a strategic move to prepare for potential tariff increases and ensure they had enough stock for Prime Day. But that decision has also strained the company’s finances, tying up capital in unsold goods. 

“Our cash conversion cycle is now drawn out because we’ve paid upfront for this inventory, and it now can take four to five months to see that payback come,” Coxe said. 

Still, Coxe said she’s optimistic that some sellers, particularly Chinese manufacturers, may struggle to compete this year, leaving more room for brands like Flaus to win on ad bids and organic search rankings. “There’s going to be less competition,” she said. “That gives brands like ours more bandwidth to bid competitively on both branded and non-branded keywords.”

Adam Wilkens, founder of Amazon consultancy Dotcom Reps, which has about 30 clients, said that while some of his clients initially planned to sit out, many are now reversing course in light of sluggish sales. 

“Sales have been soft, so some brands that were going to skip are jumping back in,” Wilkens said. “They’re doing the math and deciding they’d rather protect revenue, even if it means sacrificing margin.”

Others are getting creative. Flaus is leaning into scrappy tactics, like gifting products to TikTok creators who post “Prime Day haul” content. The company is also targeting media outlets that round up Prime Day deals, hoping to secure unpaid placements that drive volume. “We don’t have a budget for splashy brand campaigns right now,” Coxe said. “Everything has to be ROI positive.”

Rising expectations

U.S. shoppers are expected to spend more than $17 billion online during this year’s Prime Day, according to a forecast from eMarketer. That’s up sharply from last year when consumers spent $14.2 billion. Amazon, meanwhile, is projected to capture three-quarters of all U.S. e-commerce spending during the four-day period, up from just under 60% during last year’s two-day event, eMarketer also found. 

That makes Prime Day not only a sales opportunity, but also a crucial moment for brand visibility and market share. Sellers who sit out or underperform could fall behind for the rest of the year.

“If you’re a marketer, Prime Day is never optional,” said Jon Cohen, AquaSonic’s CMO. “It’s where you get return on your investment, especially if you’ve been doing top-of-funnel marketing in the weeks leading up.”

Still, the extended format has raised questions about demand. Some sellers wonder whether shoppers will spread out their purchases over four days, reducing urgency and making it harder to sustain momentum.

“I wouldn’t anticipate that sales are going to outright double just because the deal duration has doubled,” Dama said. “We’ll see a marginal increase.”

For sellers like Monil Kothari, founder of House of Brilliance, tariffs and rising commodity prices have thrown a wrench in long-term forecasting. His fine jewelry brand is still planning to participate in Prime Day, but with a leaner strategy. Discounts will be less steep, and ad spend will be 15% less compared to last year.

“Instead of discounting an item by 30%, we might only discount it by 10% or 15%,” he said. “But there is going to be increased traffic, and I’m not in a position to say no to that.”

In lieu of discounts, some of Wilkens’s brand clients are increasing pay-per-click ad spend during Prime Day, believing that the increased site traffic can lead to more sales, even without offering significant price cuts. As Wilkens put it, “Traffic equals sales, even if there’s not a lower price.”

Despite concerns, the consensus among sellers is clear: Prime Day still matters. Indeed, big box and specialty retailers, including Walmart, Target and Kohl’s have announced parallel summer sales of their own — many of which are happening earlier and longer than ever. Prime Day has become too big to ignore since its initial launch in 2015.  

As AquaSonic’s Cohen put it, “We’re expecting this to be the biggest Prime Day ever.”

What I’m reading

• Amazon will bring same- or next-day delivery to more than 4,000 smaller cities, towns and rural communities by the end of the year, the company announced.
• Target is piloting a direct-to-consumer shipping service that sends products straight from factories to customers’ homes, mirroring the model used by fast-fashion platforms like Temu and Shein, per Bloomberg. 
• Amazon’s Premium Beauty business — featuring luxury brands like Estée Lauder and L’Oréal — could be a buffer against tariffs ahead of the upcoming four-day Prime Day event, according to Reuters.

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