What document serves as evidence of a client's investment in a UITF?

The Confirmation of Participation (COP) serves as the official documentation that evidences a client's investment in a Unit Investment Trust Fund (UITF). This document confirms the investor's participation in the trust and includes vital information such as the amount invested, the number of units purchased, and the applicable NAV (Net Asset Value) per unit at the time of investment. By providing this confirmation, the COP signifies that the client has rights and ownership in the UITF, making it a crucial part of the investment process.

The other options do not serve this specific purpose. The Investment Management Agreement is more about defining the terms under which investment management services are provided, without confirming the individual investment. The Know-Your-Customer Form is primarily for compliance and due diligence purposes to gather client information rather than serving as proof of investment. The Escrow Agreement involves the handling of funds in escrow and does not directly relate to the confirmation of an investment in a UITF. Thus, the COP is the essential document that confirms and evidences the client's stake in the UITF.