Black Friday is possibly the biggest shopping day of the year.

But at least two retailers have made a surprising choice not to cash in on the money-making opportunity. It's a bold move, as the previous Black Friday brought in $151 million in sales, CNBC reported in November 2015.

Sporting goods store REI has decided to close shop on Black Friday for the second year in a row. REI will be closed on Thanksgiving as well.

“Instead of feeding the Black Friday frenzy, we’re closing our 149 stores and giving our 12,287 employees a paid day off,” REI posted on its website, the Los Angeles Times reported.

REI's website has continued its #OptOutside campaign to encourage others to do something active on Black Friday:

REI - rei.com

Outdoor Research, an outdoor apparel retailer, joined REI in saying it would be closed on Black Friday, also for the second year in a row.

Outdoor Research is closed on Thanksgiving and Black Friday this year. Outdoor Research wrote on its site last year that the company was inspired by REI's #OptOutside movement.

“The REI campaign resonated powerfully for us, because it aligns with our own values," Outdoor Research CEO Dan Nordstrom said last November, according to the brand's website. "Our core purpose at Outdoor Research has always been to inspire more people to get outdoors and through that experience better understand themselves and our planet. It’s an easy decision to join with REI employees and get outside on Black Friday."

Dozens of stores will be closed on Thanksgiving, but not on Black Friday.

That renders REI and Outdoor Research's decisions to opt out all the more significant.

Ramon Avila, a marketing professor at Ball State University, told Phily.com that it's important not to overwork retail employees this time of year:

"With the economy in much better shape, these same workers could be facing larger crowds than in previous years. They will be dealing with more inventory and customer issues than ever before. You can't expect them to be fresh and work the entire holiday season by having them come in on Thanksgiving, too."