Identifying Violations of Market Manipulation Standards

As a financial analyst at a major investment firm, you discover that one of your colleagues is consistently engaging in trading activity that appears suspicious. They are conducting transactions in a manner that can mislead the market about the available supply and demand for a security, effectively creating a false appearance of trading volume. This behavior raises concerns about potential market manipulation.

The CFA Institute Code of Ethics and Standards of Professional Conduct prohibits practices that distort market integrity and undermine the trust in the financial markets. Given this context, which of the following actions would best describe a violation of the integrity principle related to market manipulation?