There are four ethical components of the IMA of the United States (Institute of Management Accountants): competence, confidentiality, integrity, and credibility.
These components mirror why business ethics are important in managerial accounting. First, if a managerial accountant is not competent at their profession, they will be unaware of important rules and regulations and laws locally, state-wide, and federally. This could jeopardize the organization substantially.
Second, if the managerial accountant is not confidential about financial matters and uses their access to information for unethical purposes or gain, it could ultimately result in a company going under and many people losing their livelihoods.