Overlap reports help advertisers to see overlap of audiences across their brand portfolio.

The correct answer is False because overlap reports do not specifically help advertisers see the overlap of audiences across their entire brand portfolio. Instead, these reports are designed to show the overlap of audiences between different advertising campaigns or audience segments within a specific context, rather than across an entire brand portfolio. This means that while overlap reports can provide insights into audience similarities within certain campaigns, they do not give a comprehensive view of audience overlap across all brands a company may own, making the statement false.