Among Cox's notable legislative successes as a Representative was the Internet Tax Freedom Act, a 1998 law prohibiting federal, state, and local government taxation of Internet access and banning Internet-only levies such as email taxes, bit taxes, and bandwidth taxes. With U.S. Rep. Barney Frank (D-MA) as his chief co-sponsor, Cox authored legislation in 1997 to privatize the National Helium Reserve, which was then $1.4 billion in debt to taxpayers. As of 2004, this was the third-largest privatization in U.S. history, surpassing the value of the 1988 Conrail privatization. Cox also wrote the only law that was enacted over President Bill Clinton's veto, the Private Securities Litigation Reform Act of 1995, aimed at protecting investors from fraudulent and extortionate lawsuits.