If by deferred benefit plan you are referring to retirement plans for self-employment earnings, there are limits for the different types of plans. It could be possible to contribute 100% of your profit depending on the type of plan you set up and the amount of earnings.
For a SIMPLE IRA You can contribute up to $16,000, or $19,500 if you are 50 or older, as long as that doesn’t exceed your earnings. Other plans, like a SEP, limit the contribution amount to 25% of your net earnings.
Here is a great resource: https://www.irs.gov/retirement-plans/retirement-plans-for-self-employed-people
Hope this helps!
Cindy
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