If I understand your questions correctly - the answer is
Percentage of ownership is the ratio of share owned divided by total shares issued. Therefore, if the corporation issues 70 shares to you and 30 shares to another person (in exchange for capital) then - at that moment you would own 70% of the outstanding shares.
As a side comment - selling 30% of the company for $10 million would require you to justify a $33.3 million valuation (post money) on your business.
Contact me directly if you want to discuss your specific situation.
Sorry - I mis typed. Thanks for the correction.
You`ll need to speak with a professional. There are many options for deal structure. Can the venture start on a smaller scale?? You will need to show some results before going for $10M.
You have a .001% chance of raising millions of dollars for an unproven start-up unless you have a long history of home runs behind you. My advice would be to start small, prove it locally, then go for the big money.
There are several ways you might go to acquire capital for your business. Each approach will have positives and negatives. Developing your optimum capital strategy is a good next step.
Contact me off forum if you want to discuss specifics about your situation.