Source: SEASTOCK / Getty Images
5. Amazon.Com, Inc.
> Industry: Online Book Sales
> Market share: 81.3%
> Second major player, market share: Apple Inc. — 4.0%
Source: Courtesy of Courtesy of MindGeek
4. Mindgeek Llc
> Industry: Adult & Pornographic Websites
> Market share: 81.6%
> Second major player, market share: No other major player in data
Source: Public Domain / Wikimedia Commons
3. QVC, inc.
> Industry: Cable Shopping Networks
> Market share: 88.4%
> Second major player, market share: Imedia Brands, inc. — 3.1%
Source: Sundry Photography / iStock Editorial via Getty Images
2. Intuit Inc.
> Industry: Tax Preparation Software Developers
> Market share: 92.8%
> Second major player, market share: H&R Block, Inc. — 6.9%
Source: blueshift12 / Flickr
1. United States Postal Service
> Industry: Postal Service in the US
> Market share: 99.1%
> Second major player, market share: No other major player in data
