Reading a Chart: Trends, Supply and Demand, Support and Resistance

What a chart is and what it isn't

A chart is a picture of price over time. That's the whole definition. The horizontal axis is time, the vertical axis is price, and every mark on it is a record of what somebody actually paid. A two-year daily chart shows two years of trading, one mark per day.

That last sentence is worth sitting with, because it contains the honest limit of everything in this lesson. A chart is history. It is a record of transactions that already happened. It does not know what happens next, and neither does anyone reading it.

Technical analysis — studying price and volume history to judge probable future movement — starts from the idea that the record is worth reading anyway. Not because the past repeats, but because the chart is the only place where the market's collective opinion is written down in numbers. What a chart gives you is a clear view of current conditions and of how the crowd has behaved at particular prices before. What it doesn't give you is the future. Anyone who tells you a chart predicts is overselling the tool.

The other thing to know up front: charts have a lot of detail, and most of it is noise. The skill this lesson builds is telling the difference between a detail that means something and a wiggle that means nothing.

The three trends

A trend is the general direction of price — up, down, or sideways.

The word makes people picture a straight line, and that picture is wrong in a way that will cost you. Price almost never travels in a line. It moves in waves: up a while, back a bit, up further, back a bit. Peaks and troughs. Highs and lows. The trend isn't the line — the trend is the pattern the highs and lows make.

There are three of them, and each is defined by that pattern.

An uptrend is higher highs and higher lows

An uptrend is a sequence of higher highs and higher lows. Price rises to a peak, falls back to a trough that sits above the last trough, then rises to a peak above the last peak. Then again. Each pullback stops short of undoing the last advance, so the whole structure climbs like a staircase — with the steps being the pullbacks.

Read that definition as a test you can apply rather than a shape you squint at. Take the recent peaks: is each one higher than the one before it? Take the recent troughs: same question? If both are yes, it's an uptrend. The uptrend is over when that sequence breaks — when a trough undercuts the previous trough, or a peak fails to clear the previous peak.

Traders who expect prices to keep rising are bullish. The plain way to act on that expectation is a long trade — you buy the stock to open the position and sell it to close.

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Something worth admitting now rather than later. In hindsight, on a finished chart, an uptrend is obvious — you can see all the peaks and all the troughs at once. In real time you cannot. You are standing at the right edge of the chart, and the dip in front of you might be a higher low forming, or it might be the first lower low of a new downtrend. There is no way to tell which until it has already happened. Every technique in this course is a way of managing that uncertainty. None of them removes it.

A downtrend is lower highs and lower lows

A downtrend is a sequence of lower highs and lower lows. It's the mirror image: each rally stops below the last rally's peak, and each decline carries below the last decline's trough. Same test, reversed. As long as the peaks keep failing lower and the troughs keep breaking lower, the stock is in a downtrend.

Traders who expect prices to keep falling are bearish.

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A sideways trend is roughly equal highs and lows

A sideways trend is a sequence of roughly equal highs and roughly equal lows. Price bounces between a rough ceiling and a rough floor, going nowhere in particular. Technicians call this consolidation — price is contained, not breaking out either side.

One distinction here that people miss. A sideways trend has identifiable highs and lows at repeatable levels — the ceiling and floor are real, and price keeps finding them. That's different from a stock that drifts around with no clear levels at all. The second thing isn't a sideways trend. It's the absence of a trend, and it tells you nothing you can act on.

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Why trend comes first

Technicians look at trend before anything else, and the reason is a claim about probability, not certainty. The belief is that a stock going up is somewhat more likely to keep going up than to reverse, and the same in reverse for a stock going down — so trading in the direction of the trend puts the odds slightly on your side rather than slightly against it.

"Somewhat more likely" is doing real work in that sentence. Trends end. Every trend that ever existed ended. Trading with the trend is not a prediction that this one won't.

Why trends happen: supply and demand

Everything above describes what price does. This section is the why, and it's the foundation the rest of this course is built on. If you take one thing from this lesson, take this one — because once you understand it, support and resistance stop looking like lines somebody drew for mystical reasons.

Video coming soon

This lesson explains the idea in full without it.

Supply is the number of shares people are willing to sell at a given price. Demand is the number of shares people are trying to buy at a given price. A stock price is nothing more exotic than the number where those two quantities currently balance.

When more people want to buy than there are shares offered, buyers have to bid higher to find someone willing to sell. Price rises. When more people want to sell than there are buyers, sellers have to accept less to find someone willing to buy. Price falls. That's it. That is the entire engine. Every chart pattern you will ever see is this mechanism, running.

Now run each of the three trends through it.

An uptrend is demand repeatedly outrunning supply

Demand exceeds the supply available at the current price. Buyers reach higher to find shares. Price climbs — traders call this a rally.

It doesn't climb forever, because higher prices tempt more holders to sell. Somewhere up there, the new sellers coming in match the buyers, and the advance stalls. That's the peak. Now the sellers outnumber the buyers, and price falls back — a pullback, also called a retracement. It falls until the lower price tempts buyers back in, they match the sellers, and it stops. That's the trough.

Then, if demand is still genuinely strong, the whole thing repeats from a higher floor. Rally, stall, pull back, stop, rally again. Higher highs and higher lows aren't a shape. They're a scoreboard showing buyers winning each round by a little.

Why the pullbacks exist at all

Here's a piece of the mechanism that explains a lot of chart behavior.

Institutional investors — mutual funds, pension funds, insurance companies, and other large money managers — don't buy the way you do. When one of them decides to own a stock, it wants a position worth an enormous amount of money, far more than the shares on offer at today's price.

Watch what happens if such a buyer put the whole order in at once. Demand would massively exceed supply, price would spike to wherever enough sellers finally appeared, and the fund would have paid that spiked price for most of its shares. Then, with the buying finished, price would sag back toward where it started — and the fund would be sitting on a large loss it created itself.

So they don't do that. They buy a slice at a time. Buy for a few days, nudging price up. Stop. Let it drift back down as the buying pressure lifts. Buy another slice at the better price. Stop again. Repeat.

That deliberate, patient accumulation is a real reason charts step upward instead of sliding upward. The pullbacks in an uptrend are, in part, a large buyer taking a breath.

A downtrend is supply repeatedly outrunning demand

Unwinding a big position has the same problem in reverse, so it gets unwound the same way: sell a slice, let price sag — a selloff — then let it drift back up before selling the next slice into the recovery. Lower highs, lower lows.

But the symmetry isn't perfect, and the asymmetry matters. There's an old line among traders that stocks take the stairs going up and the window going down. Declines tend to be faster and steeper than the advances that preceded them. Two years of patient climbing can be undone in a few months.

The reason is human. Buying is optional and unhurried — you can wait for a better price, and greed is patient. Selling, when people are frightened, is not optional and not unhurried. Fear compresses a lot of supply into a short window. A stock that spent two years grinding from $65 to $95 can be back at $65 before the year is out, and the chart of that is not a mirror image. It's a staircase up and a cliff down.

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A sideways trend is a standoff

Consolidation is supply and demand roughly matched over a stretch of time. Neither side is winning. Price bounces between a level where sellers reliably show up and a level where buyers reliably show up.

This isn't a null state — it's an informative one. A stock consolidating between, say, $45 and $70 is telling you something specific: at $70 there is enough supply to stop any advance, and at $45 there is enough demand to stop any decline. Those two facts are the raw material of the next section.

A standoff continues until something breaks it. Usually that something is new information — an earnings report, a change in the business, news that makes people reprice the company. New information changes what people think the stock is worth, which changes how much they'll buy or sell at each price, which is a change in supply and demand, which moves the price out of the range. A breakout is price moving decisively through one of those levels, and it usually means the standoff is over.

Support and resistance

Areas of persistent supply and demand have names.

Support is a floor buyers keep defending

Support is a price area where buying has repeatedly stopped a decline. Price falls to it, demand shows up, and price turns back up. Think of it as a floor.

The reason it works is not that the number is special. It's that at that price, enough people are willing to buy. That's the whole mechanism, and it's why the next sentence is true: the more times price has stopped at a level, the more seriously technicians take it. Each bounce is more evidence that real demand lives there. One bounce is an anecdote. Five is a pattern.

Resistance is a ceiling sellers keep defending

Resistance is a price area where selling has repeatedly stopped an advance. Price rises to it, supply shows up, and price turns back down. A ceiling. Same logic, same evidence rule: more touches, stronger level.

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The thing nobody tells beginners: these are zones, not prices

Here is where most people go wrong, and it's worth being blunt about.

Support is not a number. Resistance is not a number. They are zones, and the width of the zone is real. A stock with support around $54 will bounce at $54.30 one time, $53.80 the next, and $54.60 the time after. None of those is a failure of the level. That scatter is the level.

Two consequences follow, and both matter more than they sound.

First: two competent people will draw different lines on the same chart. They'll pick different touches to anchor on, weight a recent bounce differently, disagree about whether one spike counts. Neither of them is doing it wrong. Support and resistance are judgment applied to evidence, not measurements read off an instrument. If you were expecting one correct answer, there isn't one.

Second: your line will get broken, and that isn't proof you drew it wrong. Levels fail all the time — that's what a breakout is. A level is a statement about where buyers and sellers have shown up before, and people change their minds. Treating a level as a promise is how you end up shocked by something completely ordinary.

Diagonal lines: trendlines

Support and resistance don't have to be horizontal. When a stock is trending, the floors and ceilings move.

A trendline is a straight line drawn through a series of highs or a series of lows to make the trend's direction visible. On an uptrending stock you connect the lows — that's a diagonal support line, and it says the floor is rising. On a downtrending stock you connect the highs — a diagonal resistance line, saying the ceiling is falling. Connect as many touches as the line will honestly reach. A line through four lows says considerably more than a line through two, because any two points define a line and prove nothing.

When a support trendline and a resistance trendline run roughly parallel, the space between them is a price channel — a moving corridor price has been traveling inside. Short-term traders use channels to frame where a move might run out of room.

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Old ceilings become new floors

One of the more useful ideas on this list, and one that makes sense once you think in terms of people rather than lines.

A level that acted as resistance months ago can act as support later on, and old support can become new resistance. Price grinds against a ceiling at $30 for months, finally breaks above it — and later, when it falls back to $30, it stops there and holds. The ceiling became a floor.

Why would that happen? Because the price is a place where a lot of people transacted and formed opinions. Some wanted to buy there and didn't, and now they get a second chance. Some sold there and regret it. The memory of a level is made of the people who remember it, and that memory is what makes the level behave. It's also why a level with a lot of history at it tends to matter more than a level with a little.

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Gaps

A gap is a hole in the chart: a period opens at a price meaningfully away from where the previous period closed, so no trading happened in between.

Gaps form when a flood of orders builds up while the market is closed — usually news that hits overnight. When trading opens, supply and demand have already moved somewhere new, and price starts there rather than walking there.

The edges of a gap often behave as support or resistance afterward, and the reason is the same as everywhere else in this lesson: a lot of people wanted in or out at that price and never got their chance, and the gap is the record of that unfilled intent. A stock that gaps down and later rallies will often stall at the bottom edge of the gap — which is now a ceiling.

Fibonacci retracement, and what to make of it

Charting tools let you mark levels on a chart. Most are straightforward — a trendline is a trendline. One deserves a word of explanation and a word of caution.

The Fibonacci retracement tool takes a completed move — a rally from a low to a high — and draws horizontal lines at fixed percentages of that move, marking where a pullback might find support. The conventional set of ratios is 23.6%, 38.2%, 50%, 61.8%, and 78.6%. They come from a number sequence described by the medieval Italian mathematician Leonardo Fibonacci, whose ratios turn up in various natural growth patterns.

So a stock that rallied from $60 to $100 has a 50% retracement at $80. If it pulls back, tests $80 a few times, and rallies from there, the tool called the level.

Be clear-eyed about what that is. The ratios are not laws of markets. They are a widely used convention — and a convention watched by enough traders that their orders cluster at those levels, which is a genuine reason a level can hold. That's a real effect, and it's also a different claim from "the market obeys a mathematical constant." Treat the levels as candidate zones worth watching, subject to every caveat in the section above, and you'll be using the tool the way it can honestly be used.

Chart styles: line, bar, and candlestick

Same price data, drawn three ways. The choice is about how much detail you want, and it's largely personal preference. More detail means more information and more noise, and there's no setting that gives you the first without the second.

The line chart

A line chart takes the closing price of each period and connects the dots. One number per day, joined up.

That's the least information of the three, which is the point. Stripping everything but the close removes most of the noise, so the trend, the highs and lows, and support and resistance tend to jump out. It's the chart you see on the news, because it's the chart that reads at a glance.

The bar chart, and the four numbers

A bar chart shows four numbers for each period instead of one. Those four numbers are the whole story, and every trader who ever looked serious was looking at them:

• Open — the first price of the period
• High — the highest price traded during it
• Low — the lowest price traded during it
• Close — the last price of the period

Each bar is a vertical line running from the low to the high, so the bar's length is the period's whole range. A small tick sticking out to the left marks the open. A small tick sticking out to the right marks the close. On a daily chart each bar is one day; on a weekly chart, one week.

The reason the open and close matter: together they tell you who won the period. Close above the open and buyers finished in control. Close below and sellers did. That's sentiment — the market's mood for that period — and reading it at support or resistance is how technicians get an earlier read on whether a level is holding or failing. A close well above the open right at a support level is demand showing up in a way you can see.

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The candlestick chart

Here is the thing that demystifies the whole subject, and it's usually left unsaid: a candlestick chart and a bar chart show exactly the same four numbers. Open, high, low, close. Nothing more. The only difference is how they're drawn.

A candlestick takes those same four numbers and renders them like this. The open and the close become the two ends of a rectangle — the body. The high and the low become thin lines poking out of the top and bottom of that body, called wicks or shadows. If price closed above where it opened, the body is hollow. If it closed below, the body is filled.

That's the entire translation. Same data, different picture.

The picture is the point, though. A filled body and a hollow body are different at a glance in a way that a tick on the left versus a tick on the right is not, so the balance of buying and selling reads faster. A long hollow body with a long lower wick at a support zone is a period where sellers pushed price way down and buyers took it all back — demand arriving, visible in one glyph. The same shape filled and inverted at resistance is supply arriving.

Make it concrete. Two days of a fictional stock, XYZ. These numbers are illustrative.

Monday as a bar: a line from $49.50 to $52.50, with the open tick on the left at $50.00 and the close tick on the right at $52.00 — the right tick higher. Monday as a candle: a hollow body from $50.00 to $52.00, a short upper wick to $52.50, a short lower wick to $49.50.

Tuesday as a bar: a line from $48.00 to $52.75, open tick on the left at $52.00, close tick on the right at $48.50 — the right tick lower. Tuesday as a candle: a filled body from $52.00 down to $48.50, a stubby upper wick to $52.75, a short lower wick to $48.00.

Same four numbers each time. Two renderings. Neither one knows anything the other doesn't.

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Candlestick charts have the most detail of the three, which means they also have the most noise. Every day's small hesitation is drawn for you whether or not it means anything. Some people find that spotting a trend through all that detail is harder than on a line chart. That's a real tradeoff, and it's why the choice among these three is preference rather than correctness.

Key takeaways

• A chart is a record of prices already paid. It's the clearest available picture of what the crowd has done, and it is not a prediction of what happens next.
• A trend is a pattern in the highs and lows, not a line. Uptrend: higher highs and higher lows. Downtrend: lower highs and lower lows. Sideways: roughly equal highs and lows. The trend ends when the sequence breaks.
• Supply and demand cause every trend. Price moves to where buyers and sellers balance, so an uptrend is buyers repeatedly outrunning sellers — and large investors buying in slices is a real reason charts climb in steps rather than straight lines.
• Support is a floor buyers keep defending; resistance is a ceiling sellers keep defending. They work because people show up there, not because a number is special — which is why more touches means a stronger level, why old resistance can become new support, and why levels break.
• Support and resistance are zones drawn by judgment, not exact prices. Two skilled people will draw them differently and neither is wrong. Expect a scatter of touches, and expect your line to fail eventually.
• Bar charts and candlestick charts show the identical four numbers — open, high, low, close — and differ only in how they're drawn. Line charts show only the close: less information, less noise.