An investor who holds a large portion of a company's shares and takes an active management role. A hands-on investor can also be called a majority shareholder, or activist shareholder. Such investors see their ownership stake in a firm as the reason to become actively engaged in the firm's decision making process.
The majority shareholders are usually hands-on investors and have a great influence on the company's management decisions. This may or may not lead to tension with company managers, who typically prefer not to be directed by single shareholders, especially when such shareholders do not have the same level of experience or business acumen as company management.