The study reveals that of the estimated US$1.6 billion spent in the month of September on Internet advertising, the top 10 Fortune 500 companies contributed less than US$50 million of that amount. Walt Disney Inc, ranked number 66 on the Fortune 500, was the leading Fortune 500 company advertising on the Web, with an estimated US$69.8million spend in September. However, seven of the Fortune Top 10 companies spent less than US$10 million on online advertising in September. Among these, Wal-Mart Stores spent nothing and Exxon Mobil, General Electric, Citigroup and Boeing spent less than US$1 million. According to John Cardona, President of AdZone Interactive, "Some of the larger companies haven't explored the value of online advertising. Sears.com was September's top advertiser on the Web, while Wal-Mart, number two on the Fortune 500 list, spent nothing. It's amazing to see the differences of who is and who isn't committed to Web advertising." AdZone purportedly tracks advertising on 1,300 web sites in the United States, accounting for more than 95% of all American Internet advertising revenue.