(Adds Amazon comment, updates Adobe numbers and shares)
Nov 27 (Reuters) - Cyber Monday was on track to become the biggest-ever internet shopping day in the United States as shoppers snapped up bargains on toys and electronics, with many more Americans shopping on their phones.
Adobe Analytics, a leading collector of e-commerce data, said Cyber Monday is expected to generate $6.6 billion in sales, up from $5.6 billion a year ago. As of 4:30 p.m. EST (2130 GMT), sales were up 16.8 percent to $3.38 billion. Revenue from smartphones jumped 41 percent over last year, Adobe said earlier in the day.
The buying frenzy has gone on for the better part of a week. Amazon.com Inc said it broke sales records this weekend and was on pace to do so on Cyber Monday, with 3 million toys sold halfway through the shopping event.
Thanksgiving and Black Friday, when shoppers spent $7.9 billion and bought more on their mobile devices than last year, had also generated record online sales.
This has brightened the overall outlook for traditional retailers that have expanded beyond brick-and-mortar outlets into e-commerce. However, the availability of deals and promotions throughout November hurt shopper traffic at stores.
Promotions during the weekend were largely uninspiring, Barclays analysts said in a note, adding that deeper discounts could continue into December rather than being concentrated on Cyber Monday.
Adobe collects the data by measuring 80 percent of all online transactions from the top 100 U.S. retailers. Of every $10 spent at the top 500 U.S. retailers, $7.50 goes through the Adobe sales platform.
Toys are expected to see the biggest discounts Monday followed by some deals on computers and televisions, Adobe said.
Wal-Mart Stores Inc started Cyber Monday deals at midnight on Monday and said it will bring back discounts from Black Friday that were popular with shoppers.
Wal-Mart is within striking distance of matching Amazon's online prices for the first time, a key milestone in its effort to regain the "low price leader" title, data gathered for Reuters show.
Amazon shares closed up 0.8 percent, while Wal-Mart and Target Corp shares were about flat. J.C. Penney Company Inc closed up 3 percent, and Macy's Inc closed up 0.7 percent.
(Reporting by Nandita Bose in New York, Sruthi Ramakrishnan in Bengaluru and Jeffrey Dastin in San Francisco; Editing by Nick Zieminski and Lisa Shumaker)