It's unclear whether the early openings will lead shoppers to spend more over the two days or simply spread sales out.
Last year, sales on Thanksgiving rose 55 percent from the previous year to $810 million, as more stores opened on the holiday, according to research firm ShopperTrak. But sales dropped 1.8 percent to $11.2 billion on Black Friday, though it still was the biggest shopping day last year.
Store sales numbers won't be available until Saturday. But IBM Benchmark, which tracks e-commerce for 800 retailers, said online sales on Thanksgiving were up 19.7 percent from last year. Online sales on Black Friday rose 9 percent, based on preliminary data.
There are signs that stores fared well, too.
Wal-Mart, the world's largest retailer, started its holiday sales events at 6 p.m. on Thanksgiving, two hours earlier than last year. Wal-Mart said customers bought at least 2.8 million towels, 2 million TVs, 1.4 million tablets, 300,000 bicycles and 1.9 million dolls.
Terry Lundgren, Macy's CEO, said the 15,000 people who showed up for the opening of the flagship store was the most ever, up from 11,000 last year. "Clearly people are in the shopping mood," he said.
Of course, not every retailer saw robust crowds.
At Woodland Hills mall in Tulsa, Okla., the owner of Bags and Bangle complained that he had to stay open from 8 p.m. on Thanksgiving to 10 p.m. on Friday. Suhail Zaidi, who was required by the mall to keep his booth open, said Thanksgiving was somewhat busy, but business had died down by 3 a.m. On Friday morning, he said he had seen only about 20 customers.
"We ruined the holiday," Zaidi said. "Black Friday is a good shopping day, but opening up on Thanksgiving is ridiculous."
AP writers Chris Carola in Clifton Park, N.Y., and Kristi Easton in Tulsa, Okla.; AP Retail Writer Mae Anderson in New York; and AP Business Writer Sarah Sell in Portland, Ore., contributed to this report.