Despite intensified competition from fierce rivals including Microsoft and Wal-Mart Stores., Apple’s iTunes store in 2010 managed to hold onto its dominance in the U.S. market for movie electronic sell through (EST) and Internet video on demand (iVOD), new IHS Screen Digest research from iSuppli (http://www.isuppli.com) shows.

The iTunes accounted for more than two-thirds of U.S. EST/iVOD movie consumer spending in 2010, at 64.5%, down from 74.4% in 2009. The company also maintained its control of three quarters of the U.S. EST business in 2010. Apple’s hold on its market share supremacy was all the more impressive given that the business underwent a significant expansion in 2010, with EST/iVOD movie revenue rising by more than 60% for the year.

“The iTunes online store showed remarkable competitive resilience last year in the U.S. EST/iVOD movie business, staving off a growing field of tough challengers while keeping pace with an dramatic expansion for the overall market,” says Arash Amel, research director, digital media, for IHS. “Apple faced serious competition from Microsoft’s Zune Video and Sony Corp.’s PlayStation Store, as well as from Amazon and — most significantly — Wal-Mart. However, iTunes managed to grow because of the introductions of the iPad and the second-generation Apple TV, which have spurred the company’s movie rental offerings and have invigorated the iTunes multi-screen ecosystem. We expect that in the United States, Apple’s strong performance in iVOD will allow it to continue to bypass the video on demand services offered by many major cable operators.”

Competition from Microsoft intensified in both the movie EST and iVOD segments in 2010 because of the highly successful launch of its Kinect 3D motion controller system for its Xbox 360 video game console. This resulted in a bumper fourth quarter for movie revenue on the Zune Video platform, cementing the No. 2 market rank for Microsoft.

Microsoft in 2010 accounted for 17.9% of U.S. movie EST/iVOD consumer spending, up from 11.6% in 2009. Sony in 2010 maintained the number three position in the U.S. market with a 7.2% share, up from 5.7%t in 2009. However, the company is facing rising competition in the United States by Amazon VOD — and Wal-Mart’s Vudu service.

While these major players continue to ramp up the competitive pressure on Apple, the most fearsome rival for iTunes in the future could be a giant company that was only a small player in 2010: Wal-Mart. Wal-Mart’s aggressive drive for market share for its U.S. online movies service Vudu, has generated a spike in consumption for the service starting in the fourth quarter of 2010. The company announced $0.99 promotional pricing on iVOD movies and support for a wider range of living room devices, including Sony’s PlayStation 3 video game console.

“The future of the online movie business may come down to competitive battle between Apple and Wal-Mart,” Amel says. “Although Wal-Mart is not on the charts yet, the company soon will become a major player if its current momentum continues. The company already represents a critical source of revenue for the major Hollywood studios because of its massive sales of Blu-ray and DVD movies — and now is expanding this business into the online realm.”

Wal-Mart generated more than $3.5 billion in revenues to the studios from sales of physical movies in 2010, IHS Screen Digest research indicates.