(MP) Stands for “Time Price Opportunity”.  It is the smallest unit of measure displayed any market profile graphic, denoted by a single letter.  Each TPO represents a point of time where the market being charted trades at a specific price.  A single TPO is printed on the chart every time that a certain price is touched during any time period.  Typically, the periods are set to 30 minutes.  Therefore, every different letter that you see in the market profile distribution denotes a different 30 minute period.