EIN
Employer Identification Number — 9-digit IRS-issued tax ID used on Form 5500-EZ.
Definition
An EIN (Employer Identification Number) is the 9-digit federal tax ID assigned by the IRS to a business entity. The plan sponsor's EIN appears on Form 5500-EZ line 2b. Sole proprietors who use their SSN for business taxes must still obtain an EIN to file Form 5500-EZ.