Doctor participates in SIMPLE plan and is currently deferring the maximum. Has unrelated self-emplpyment income and wants to set up a Solo 401k for this. What is the maximum that he can contribute to the Solo 401k? Are the deferrals here reduced by the SIMPLE contributions?

Assuming that a controlled group or affiliated service group issue does not exist, the deferrals to the k plan will be limited by the total amount of deferrals under the SIMPLE. Deferrals are an individual limit and all deferrals must be aggregated for purposes of the limit. The doctor would still be entitled to the profit sharing contribution as well as the remainder of the deferrals.

Dr is limited to the max deferral under the k plan minus the SIMPLE deferral. Pub 560, P10. He can still deduct 20% of net earnings from med practice (less 1/2 SECA tax) contributed to a PS plan up to 42k max.