When an unemployment claim is filed by an individual, a "Notice of Application for Unemployment Compensation" (OES-617) is mailed to the separating employer and all base period employers.
The separating employer is a claimant's most recent employer before they filed for unemployment benefits.
A base period employer is any employer that reported wages on their quarterly report for the claimant in question during the claimant's base period. The base period is the first four of the previous five completed calendar quarters from when the claimant filed their initial claim. This means employers may receive a notice for a former employee who separated anytime during the previous year and a half.