When the documentation for the basis of an uncovered security is missing, it can lead to reporting problems for brokers. 

The rules requiring brokers to report basis when stock is sold only apply to stocks acquired on January 1, 2011 or after. Even so, many brokers will report basis information, when known, for uncovered securities, such as those purchased before 2011 or otherwise not considered a covered security. Not only do clients need to confirm that the basis information reported by the broker is correct, but they may need to supply basis information for stocks for which the broker has no basis information. If the taxpayer cannot prove their basis amount (such as with trade confirmation tickets or brokerage statements), there may be no option but to use a zero basis. Sometimes internet research can help. For example, say a client inherited stock but doesn’t know what the value was on the date of death, but does know what that date was. Using web sites such as http://bigcharts.marketwatch.com/historical/ to get the historical data could provide enough information to establish a basis.

Issuers of “specified securities” are required to file Form 8937, Report of Organizational Actions Affecting Basis of Securities, with the IRS when events occur such as nontaxable cash distributions or nontaxable stock distributions to shareholders, including stock splits. The report need not be filed with IRS and a copy is not required to be given to individual shareholders if the company posts a completed copy of the 8937 on its web site and keeps it accessible to the public for 10 years. The information included on the form may be helpful in determining basis when there have been mergers or spin-offs and your client doesn’t have the details of how their original basis should be adjusted.