Previous Day Open, High, Low, Close

Previous Day Open, High, Low, Close (often shortened to "prior day OHLC") refers to the four benchmark prices from the last completed trading session: the first traded price of the day (Open), the highest traded price (High), the lowest traded price (Low), and the last traded price (Close). Together they summarize an entire day of trading in four numbers.

Traders plot these levels on the current day's chart as horizontal lines. Because they come from a full session of buying and selling, they tend to mark places where real supply or demand showed up before, so price often reacts when it revisits them. A stock trading above yesterday's high is showing strength relative to the prior session; trading below yesterday's low is showing weakness; a price sitting between yesterday's open and close is often described as being "inside" the prior day's range.

The nuance that trips beginners up is treating the open-to-close spread as a measure of "momentum" in the sense of speed. It isn't a speed measurement — it just tells you where price ended up relative to where it started, netting out everything that happened in between. A stock can open at 50, spike to 60, crash to 40, and close back at 51; the open-to-close difference looks small even though the day was extremely volatile. That's why high and low (the full range) and open-to-close (the net result) are describing two different things, not two versions of the same thing.

It's also worth remembering these are fixed reference points from a session that has already ended — they don't move during today's trading. That fixed, known-in-advance quality is exactly why so many traders use them as levels to watch, rather than as a live indicator.