The penalties for filing a late Partnership Tax Return are $50 per partner multiplied by the number of months that the partnership has been delinquent in its filing of its partnership tax return.
Therefore, for a 3-member partnership return that has been 4 months late in its filing of its Partnership Tax return, the penalties would be $50 x 3 x 4 = $600.
However, please review the link below to determine whether there are possible grounds to have the penalties abated for your particular situation.
Can the IRS abate the late filing penalty for an LLC or Partnership?