A K-1 is issued to an owner/investor in the entity. A 1099-MISC is issued to a subcontractor of the entity. A 1099-B is appropraite for the trading of securities for your own account. Some traders are issued a 1099-MISC showing the net income, which might be appropriate if they are truly a subcontractor using the money of the firm and merely getting a percentage of the gains paid to him for his services. When there are no net gains, rather there are net losses, this method falls somewhat short and it is up to the individual to properly maintain his sole proprietorship records along with his letter of agreement, to reflect his reportable tax numbers.
I am a prop trader and I get a k1. My firm is considering changing the reporting to a 1099. I will be getting a 1099b. I am wondering if I will have to pay more taxes after the change. I did not have to pay self employment tax last year but if I get a 1099 would I need to pay self employment taxes?
The tax form itself does not actually identify if you owe self-employment taxes, per se. (though it implies if you do or not) The 1099-B only lists the sales, not the purchases, therefore you are responsible to provide the gains/loss computations. Since the firm knows the purchases you made, that hopefully would be provided to you as a supplimentary item - same as many retail brokerages do.