Hey Chris,
Your friend's 30% stake entitles him to 30% of shareholder's equity which is defined as Total Assets - Total Liabilities. It also entitles him to 30% of net income less plowback. By definition, that's what a 70-30 sharing formula amounts to.
You have the alternative of paying yourself a salary since you are the active manager of the business. So the sharing formula becomes 70-30 of Net Income less your salary which could either be a fixed amount or preferably (in order to ensure incentive alignment), a percentage of Revenue - Expenses.
If you made $1 Million in Net income and your management salary is 10% of that. You get $100k and then you and your friend share the 900k at the 70-30 ratio. Effectively, in this scenario, you get 73% and he gets 27% but he still owns 30% of the business. You can tinker with the management salary percentage to further tilt things in your favor as long as he agrees (though you are the majority owner and theoretically and legally, you can do whatever you want).
He is aware that he owns 30% of the venture so he should not be expecting to split profits 50-50. The fact that you are doing the same amount of work doesn't mean much really. There must have been some basis for the 70-30 split (perhaps sweat equity premiums for all the work you did before he came on board and so on) so that's really how to share the net income after all expenses (including your salary).
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