as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
why do people sell when demand pushes share price up?
user
you are assuming the price increase will continue. the people selling are assuming that the price increase will not continue.  ultimately that's what a share transaction is: one person would rather have the cash at a particular price / time, and one person would rather have the share.
assistant