In 2015, 100% of net adjusted business profits income up to the maximum of $18,000 or $24,000 if age 50 or older can be contributed in salary deferrals into a Self Employed 401k (2014 limits are $17,500 and $23,000 if age 50 or older). Profit Sharing Contribution :n 2015, 100% of W-2 earnings up to the maximum of $18,000 or $24,000 if age 50 or older can be contributed to a Self Employed 401k (2014 limits are $17,500 and $23,000 if age 50 or older). Profit Sharing Contribution :