The Wharton School’s Barbara Kahn explained why Black Friday seems to start earlier and last longer each year. “When someone is offering 50 percent discounts from 10 to 11 on Friday, you can offer 51 percent from 9 to 10 on Friday. That competitive response will cause the creeping behavior — it’s getting earlier and earlier — because you want [customers] to buy from you instead of the competition,” said Kahn.

November 20, 2018 ・ From Vox.com