Lots of folks are enjoying their new holiday gifts right now — but some might not love that new sweater. The week following Christmas is the biggest week of returns in the U.S., and this year, some major retailers are making some major changes to their return policies.

Outlets including Amazon, REI, and Target are changing who can return items and how they return them. It's to combat fraud, which has cost retailers tens of billions of dollars each year. And while you might not be trying to game the system, the changes will affect you nonetheless.

In June, Amazon added processing fees for high-return items. That charge varies, since it's based on an item's popularity and how often it's returned. But shoes and apparel are excepted due to sizing issues — so you can still get rid of those reindeer socks without a penalty.

Outdoor retailer REI also announced it could refuse a return — but that's limited to frequent returners. The company says the changes will affect only 0.02% of members who show a pattern of policy abuse.

Similar changes are at Target, which announced it reserves the right to also refuse refunds suspected of fraud.

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The changes come as cases of fraud have increased in recent years. The National Retail Federation estimates return scams cost retailers over $100 billion in 2023 alone. That's after $743 billion in items were returned. By the end of 2024, the group estimates that number will rise to nearly $900 billion.

Online shopping it where most returns occur. According to the software company Elite Extra, the cost of handling a return is roughly 17% of the purchase cost. So for every $100 in accepted returns, a company loses $17.

You can thank the "wardrobers" out there who return used items, or the folks who fake receipts for stolen goods. Or those who switch high-value items with knockoffs.

And don't forget to thank Dear Aunt Sally for the sweatshirt. She meant well.