Target Corp. is pledging to match prices of select online rivals year-round, a move that underscores how physical and online retailing are being meshed together.

Matching online prices is rare but expected to become more common as shoppers move increasingly online. Target, the nation’s second largest discounter behind Wal-Mart Stores Inc., said it will match prices that customers find on identical products at top online retailers, all the time. The online list includes Amazon.com as well as the websites of Wal-Mart, Best Buy, Toys R Us and Babies R Us.

Target’s move follows a similar holiday price match that began Nov. 1 and ended Dec. 16. Target is also making permanent its holiday offer of matching prices of items found at its stores with those on its website. And for the first time it will include products that are out of stock on Target.com.

The moves follow a disappointing holiday shopping season for the Minneapolis-based retailer, hurt by stiffer competition from online rivals and stores like Wal-Mart that have hammered its low prices. It’s also the latest step from brick-and-mortar stores to combat “showrooming” — a growing trend for customers to browse stores to check out products, and then go online to buy the same products for less.

Mark Schindele, Target senior vice president of merchandising operations, noted the discounter monitors prices of 30,000 items, and thousands more online, to make sure it’s competitive. But Target says it had to do more to give shoppers more confidence.

Many major stores have offered price matching guarantees for local competitors’ brick-and-mortar stores, but it wasn’t until this past holiday season that the focus was on matching online prices. Analysts believe that the trend will increase as stores are realizing they need to wake up to the increasing shift among consumers to online, which accounted for about 10 percent of holiday sales this past season.