25% is incorrect. The maximum permissible contribution under the partnership's SEP plan is 20% of net earnings from the partnership and the contribution for each partner must be determined using the same percentage of net earnings. (In other words, the maximum SEP contribution for the 51% partner would generally be about 4.08% higher than the contribution for 49% partner, assuming that it is not the case that one partner's self-employment tax was limited by paying Social Security tax with another employer while the other partner's was not.) Net earnings are the amount of income reported as self-employment income with code A in box 14 of the partner's Schedule K-1 reduced by the deductible amount of that partner's self-employment tax.
If the maximum permissible SEP contribution is being made, TurboTax will calculate the correct maximum SEP contribution when you mark the Maximize box for a SEP contribution.
