I have 401(k) through work that gets contributed monthly and it has maxed out contributions for the year ($18K).
My wife doesn't have 401(k) and is self employed. If she opens 401(k) at the end of the year (November) can she contribute up to the maximum $18K in one payment and will contribution count tax free? Or is there some rule how much you can contribute per month?
Context: She made more than $18k for this year. We are filing jointly total income will be $200k+