Henning Gilberg, 25, initially intended White Monday as marketing for his e-repair start-up Repamera, but he has managed to get Myrorna, Sweden's biggest chain of second-hand charity stores, to join him, as well as Sellpy and Hygglo, two the most successful start-ups in Sweden's "circular" and "sharing" economy.
"The interest is right now massive," Gilberg said. "Black Friday is based on new consumption: buy something and throw the old thing out. White Monday is the total opposite."
Uniting behind the initiative are different companies where, for example, you can rent clothes or tools, or you can eat food that was going to be thrown away.
Oksana Mont, professor in environmental economics at Lund University, welcomed the initiative as a good way to raise awareness, but warned that the jury is still out over whether the sharing and circular economies reduce consumption.
"There is a hope that the sharing economy will help us reduce our consumption levels and thereby reduce environmental impacts," she said.
But, she says, people do not stop purchasing new items, just because they start sharing some things with others.
"People tend to do both. They consume newly produced goods and they also get access to different items via sharing," she says.