Generally, a majority owner has the right to control the decision-making of the company. However, he runs into a possible conflict of interest/fair dealing situation if he hampers the business's credit to do a deal that the business will not profit from. In addition, the investment in a business of a potential competitor is problematic, as business owners have an obligation to place the interests of the business first.

If you have a shareholder's (or other ownership agreement) in place, there may be rules about the voting percentage needed to authorize an "interested" transaction of this type (such as, simply 51 percent majority isn't sufficient; you might need 66 2/3 percent).

You have some thorny issues here and would be well-advised to speak with an attorney about your situation.