More than 20 million Americans have multiple Social Security numbers associated with their name in commercial records, according to ID Analytics, Inc., a consumer risk management company. Rather than serving as a unique identifier, more than 40 million SSNs are associated with multiple people, the company says.

Using its database, the company examined more than 280 million SSNs to determine discrepancies, and finds that 6.1 percent of Americans have at least two SSNs associated with their name; more than 100,000 Americans have five or more SSNs associated with their name. The company also finds that some SSNs are very popular: more than 15 percent of SSNs are associated with two or more people, more than 140,000 SSNs are associated with five or more people, and more than 27,000 SSNs are associated with 10 or more people.

While most of the discrepancy is due to data entry errors in business transactions that use SSNs, some duplication is also likely linked to fraud, the company says.