Shipping company UPS says return activity will likely peak on Jan. 2, when it expects roughly two million packages to be sent back to retailers.

“Retailers are having to spend more operating expense on taking returns, processing returns, moving returns than they ever have before as more business moves online and the competition gets stiffer — not just for one-day shipping, but also for fast and seamless returns processes,” said Joel Bines, a managing director of retail analysis at AlixPartners.

But there may be a silver lining for retailers.

“A lot of these returns happen in-store and anytime a consumer is in a store, there’s an opportunity for them to buy more things,” said Mark Mathews, head of research at the National Retail Federation.

It’s also cheaper for stores to process returns in-store. It costs retailers $3 per package when items are returned to stores and twice that when they’re shipped to a distribution center.