Major online retailers have enjoyed sizable year-over-year web sales growth so far this holiday shopping season.

Data from Slice Intelligence shows that Costco Wholesale Corp., No. 9 in the Internet Retailer 2017 Top 500, has emerged as one of the biggest winners of the holiday shopping season this year, posting year-over-year online sales growth of 59.8% from Nov. 1-Dec. 15. Slice bases its estimates on data from a panel of 5 million online shoppers in the U.S.

Here’s a look at how much online sales are up for other major retailers so far this holiday season, according to Slice:

• Target Corp. (No. 20): 54.3%
• Kohl’s Corp. (No. 18): 41.6%
• Wal-Mart Stores Inc. (No. 3): 31.8%
• Best Buy Co. Inc. (No. 10): 26.0%
• Amazon.com Inc. (No. 1): 23.1%

Slice estimates that total online sales are up by 23% so far during the holiday season compared with last year.

Meanwhile, just-released data from the Mastercard Spending Pulse shows that the electronics category has been the big winner so far in terms of year-over-year online sales growth. Total online sales increased 16.3% from Nov. 1-Dec. 20, while electronics (23.8%) and home improvement (20.7%) have generated the strongest sales growth among individual product categories, Mastercard estimates.

Retailers continue to make an effort to reach last-minute shoppers. For the second year in a row, Kohl’s is keeping its stores open 24 hours through Christmas Eve. Kohl’s emailed shoppers on Thursday morning informing them that stores will be open continuously from 7 a.m. Thursday through 6 p.m. on Christmas Eve.

Amazon emailed Prime customers on Thursday morning informing them that they have until the end of Friday to place an order and have it arrive in time for Christmas using free two-day shipping, which is included in their annual Prime membership that typically costs $99 a year.

On the eve of what is traditionally one of the busiest times of year for online returns, Happy Returns, a company that works with online retailers to accept returns of online purchases in high-traffic areas like shopping malls, has landed an $8 million funding round and expanded to 50 locations in 14 markets.

This latest funding round was led by venture capital firm USVP and brings the total amount raised by Happy Returns to $14 million, according to CrunchBase. Happy Returns operates “Return Bars” where shoppers can return orders from participating online retailers. Happy Returns takes care of repackaging and shipping.