Multiple K-1s, net negative, can owner defer from positive K-1?

[401(k)athryn]

Five companies have adopted a plan.  There are three owners.  Company A & B are owned 100% by owner 1.  He also owns 33% of company C.  Company A and C have negative self-employment earnings on the K-1.  Company B is positive income.  When combined, the net income is negative.  Can he defer from the positive compensation earned through Company B?

I think the other way to ask is - do I consider the compensation from Companies A & C to be ZERO or do I actually use the negative number when determining 415 compensation? 

Thanks,

Kathryn 

[Bird]

Well, I think I would net it all and get a negative number.  If there were companies not adopting the plan, then I think it would be appropriate to ignore any income from them.  Unless there is positive income from some other company to give a net positive for self-employment income, he would have a problem taking the deduction, which is taken on the 1040 (at least I think he needs to show positive SEI in order to take the deduction).