US Government—CIA, law enforcement and other agencies hire math majors as cryptographers and cryptoanalysts, not to mention accountants, engineers, statisticians, technicians and other math related jobs in all government agencies, state agencies and the armed forces. More than one-third of all mathematicians work for the federal government, making this industry the top employer for the career, according to the United States Bureau of Labor Statistics (BLS).
National Security Agency (NSA)-data mining, code breaking, encryption, etc.
Colleges, Universities and schools employ a large percentage of mathematicians and statisticians in research and development, as well as teaching jobs. However, most of the time these positions require advanced educations, sometimes a PhD, and are among the lowest paying jobs in the field.
Google—software engineers, data scientists, programmers
Finance and Insurance hire a large number of business analysts and actuaries.
McKinsey and Company, Boston Consulting Group and other management consulting firms hire business analysts at a high rate.
Genentech—A biotechnology firm based in California which is one of the biggest employers of biotechnicians. Math majors work well in biotech, due to the mathematical aspects of studying DNA and proteins.
Boeing, Raytheon, Lockheed-Martin and other major aerospace companies