The Internal Revenue Service shares an awareness that possbily 700,000 individuals may have been impacted by a data breach last year.  They have spotted some attempts to create false tax returns and are in process of warning additional impacted households.

http://www.nbcnews.com/tech/security/irs-cyberattack-total-more-twice-previously-disclosed-n526846

Cyberattacks on taxpayer accounts affected more people than previously reported, the Internal Revenue Service said Friday. The IRS statement, originally reported by Dow Jones, revealed tax data for about 700,000 households might have been stolen: Specifically, a government review found potential access to about 390,000 more accounts than previously disclosed.

In August, the IRS said that the number of potential victims stood at more than 334,000 — more than twice the initial estimate of more than 100,000.  Additionally, the IRS said there were 295,000 taxpayer transcripts that were targeted, but “access was not successful.” The agency said it will send mailings to affected taxpayers beginning February 29.