Market Manipulation Ethics Question

As a newly licensed investment professional, you are reviewing various practices within the trading department of your firm. You notice that a colleague frequently trades a security in large volumes just before the company announces quarterly earnings, creating a significant spike in the stock's daily trading volume. This colleague believes that such actions will attract more attention to the stock, potentially benefiting the shareholders.

Considering the CFA Institute's Code of Ethics and Standards of Professional Conduct, particularly regarding integrity and market manipulation, what should you conclude about your colleague's actions?