The best way to support the justification for investment in a new security solution is to show how the solution contributes to the business strategy of the organization. The business strategy defines the vision, mission, goals, and objectives of the organization, and the security solution should align with and support them. The security solution should also demonstrate how it adds value to the organization, such as by enabling new business opportunities, enhancing customer satisfaction, or increasing competitive advantage. The business case should include the expected benefits, costs, risks, and alternatives of the security solution, and provide a clear rationale for choosing the preferred option1.
References = CISM Review Manual, 16th Edition eBook2, Chapter 1: Information Security Governance, Section: Information Security Strategy, Subsection: Business Case Development, Page 33.