July 15 (Bloomberg) -- Walmart.com is charging $1.33 less than competitors for ``Harry Potter and the Half-Blood Prince,'' helping snare sales from Amazon.com Inc. and fueling growth at the online division of Wal-Mart Stores Inc.

Orders on Walmart.com for the sixth book about the young wizard who battles the evil Lord Voldemort jumped fivefold compared with ``Harry Potter and the Order of the Phoenix'' two years ago, spokeswoman Amy Colella said. Amazon.com, which charges $17.99 for the book, said U.S. orders rose about 14 percent.

The surge in demand for the 672-page book by J.K. Rowling reflects the growing threat that Walmart.com poses for Amazon.com, the world's largest Internet retailer. Walmart.com in May became the third most popular online retail site, up from fourth place, according to ComScore Networks Inc., a Reston, Virginia-based Internet research firm.

``We are taking share from some of our competitors,'' said Raul Vazquez, vice president of marketing of Walmart.com. ``We have started to understand our customer better,'' Vazquez said, offering products not found in stores such as hot tubs and some LCD-screen televisions.

Amazon.com, which is celebrating its 10 anniversary this month, will increase sales worldwide by 22 percent this year, a decline from last year's 31 percent gain to $6.92 billion.

Wal-Mart, the world's biggest retailer with $285.2 billion in revenue last year, said its online sales gains are running at two to three times the industry average. Web sales excluding travel rose 24 percent last year, according to Washington-based Shop.org, an online retailing industry group. Walmart.com's 2004 sales were about $782.2 million, estimates Internet Retailer magazine.

`Fight For Market Share'

Retailers including Dallas-based Neiman Marcus Group are also posting online gains bigger than Amazon.com. Neiman Marcus and Minneapolis-based Target Corp. each reported that 2004 Web sales doubled.

``As the market matures, it's becoming a more competitive,'' said Scott Silverman, executive director of Shop.org. ``We're moving from a situation where a rising tide is lifting all boats to a situation where there are fights for market share.''

Shares of Bentonville, Arkansas-based Wal-Mart rose 37 cents to $50.51 yesterday in New York Stock Exchange composite trading. They've fallen 3.9 percent in the past year. Seattle-based Amazon.com shares rose 68 cents to $37.19 in Nasdaq Stock Market composite trading. They've fallen 25 percent in the past 12 months.

Amazon.com spokeswoman Patty Smith declined to comment.

Evil Lord Voldemort

Walmart.com is selling the Harry Potter title for $16.66 compared with $17.99 at Barnes & Noble Inc. and Borders Group Inc. Amazon.com took 1.4 million pre-orders worldwide as of Tuesday. Walmart.com declined to release its sales figure.

Advance sales of the Harry Potter book are outpacing previous installments in the series and it may become the top- selling children's title in history, said Diane Roback, children's book editor for Publishers Weekly. The record is now held by ``The Poky Little Puppy,'' which has sold more than 14.9. million copies. U.S. publisher Scholastic Inc. is printing a record 10.8 million books to prepare for demand when the novel goes on sale on July 16.

Borders Group in Ann Arbor, Michigan, estimates Harry Potter will add 2 percentage points to second-quarter sales at stores open at least a year, spokeswoman Anne Roman said. The book could contribute more than 1 percent, or $19.4 million, to Amazon.com's third-quarter revenue, according to an estimate for U.S. sales.

Walmart.com

Walmart.com boosted sales in the past year after adding apparel, pet products, custom music CDs and flowers to its mix of furniture and electronics, including 60-inch plasma-screen televisions for $7,848.

Walmart.com strategy is to build market share partly by integrating its products with the company's stores, said Jim Breyer, managing partner of Accel Partners and a Wal-Mart director. This includes allowing customers to order digital photos online and pick them up in stores.

``Amazon is a full-fledged online retailer, whereas Wal-Mart uses it to drive traffic to the stores as much as get sales online,'' said Don Gher, who owns Wal-Mart shares among the $650 million in assets he helps manage at Bellevue, Washington-based Coldstream Capital Management.

The Web site's traffic rose by 37 percent to 22.6 million in June, making it the third-most visited retail site behind EBay Inc. and Amazon.com. Target's Corp.'s online store had an 82 percent increase in visitors to 19.8 million visitors during June, according to ComScore Networks Inc., a Reston, Virginia- based Internet research firm.

Free Shipping

Amazon.com's U.S. traffic growth is slower than some traditional retailers. In June, visits totaled 40.1 million, or 22 percent rise from a year earlier.

``Traditional retailers have been without a doubt posting impressive growth over the past year,'' said Dan Hess, ComScore senior vice president. ``There are a number of factors within that, including the number of new Web users who have come online over the last couple of years, many of whom decide to turn to brands they know and trust.''

To compete, Amazon.com Chief Executive Jeff Bezos, 41, has added discounted shipping programs as well as traditional retailers to his site. This year on Amazon.com Macy's and Bebe Stores Inc. joined other retailers including Nordstrom Inc., Target Corp. and J.C. Penney.

The number of items sold by other merchants, which pay a sales commission to Amazon.com, rose to 27 percent of units in the first quarter from 23 percent a year earlier.

``The competition has gotten better and some people are going to go to those competitors,'' said Martin Pyykkonen, a Janco Partners analyst who has a ``sell'' rating on Amazon.com shares. He forecasts the online retailer's sales growth will decline to 14.5 percent next year.

To contact the reporter on this story: Greg Wiles in San Francisco at grwiles@bloomberg.net.

Last Updated: July 15, 2005 00:09 EDT