The HOLP strategy was developed by trader-author John F. Carter in his book 'Mastering the trade: proven techniques for profiting from intraday and swing trading set ups' (ISBN 0-07-145958-8). The strategy, which gives buy signals, is a reversal strategy. Reversal strategies try to determine the point in time when a trend reverses direction. In his book John F. Carter is actually skeptical of taking a position against the trend, quoting classics like "never catch a falling knife" (buy a steep sell off) and "never step in front of a train" (short sell a strong market). Given his skepticism he decides to base his strategy on the one single factor which he deems relevant: the market price.