TPO structure: how the profile is built

The basic building block of the Market Profile is the Time Price Opportunity (TPO). It is simply an answer to one question: did the market offer this price at this moment in time?

Letters and periods

The trading day is divided into periods of half an hour each, and each period is given a successive letter: A for the first period, B for the second, C for the third, and so on. Whenever a given price trades during a period, that period’s letter is placed beside that price.