A defined contribution plan for which the primary investments are employer stocks ( stocks of the employer that sponsors the plan)
In order to be treated as an ESOP under the tax code, the plan must meet certain requirements, including the following:
The plan must be formally designated as an ESOP in the plan document
The plan must specifically state that it is designed to invest primarily in qualifying employer securities. As such, a money purchase pension plan or a stock bonus plan constituting an ESOP may invest part of its assets in other assets ( other than qualifying employer securities).
ERISA §407(d)(6)(A) , IRC §401(a)
Additional Helpful Information
An ESOP can be part of a defined contribution plan (other than an ESOP)
If an existing defined contribution plan is converted to an ESOP, the fiduciary and exclusive-benefit rules apply to the conversion.
According to 28 CFR 2550.407d-6, a plan constitutes an ESOP for a plan year, only if it meets other such requirements as the Secretary of the Treasury may prescribe by regulation under IRC§ 4975(e)(7)