Misrepresentation of Mutual Fund Performance

During a quarterly meeting with clients, an investment advisor discusses the performance of their firm's mutual funds. To emphasize the success of the funds, the advisor states that the funds generated returns of 15% last year, without mentioning that such returns were highly influenced by a single, unusually successful investment in a tech stock. In this case, the advisor's statement could be scrutinized under the CFA Institute's Code of Ethics and Standards of Professional Conduct.

What ethical consideration is primarily at stake in this scenario?