Regular Flat
A regular flat is a three-wave corrective pattern (A-B-C) where Wave B retraces approximately 90% to 100% of Wave A, and Wave C is roughly equal in length to Wave A. It is actually the rarest type of flat correction. Most traders expect flats to be common, but in practice, expanded flats appear far more often. In a regular flat, the pattern moves sideways in a tight range. Wave A sets the range, Wave B comes back to near the start, and Wave C drops to near the end of Wave A. The structure is 3-3-5, meaning Waves A and B each subdivide into three sub-waves, while Wave C subdivides into five. You spot regular flats when price chops sideways with minimal net progress. They tend to appear in Wave 4 or Wave B positions.
In a stock trading at $50, Wave A drops to $45 in three sub-waves. Wave B rallies back to $49.50, retracing about 90% of Wave A. Wave C then declines to $44.50, roughly equal to Wave A's 5-point length. The entire pattern takes the stock from $50 to $44.50 in a sideways grinding fashion. A trader recognizing this flat at the Wave C low would look to buy, expecting the next impulse wave to begin.