Have you ever wondered why stock prices or commodity prices go up or down?

Most people tend to think it's complicated, but in reality, it all comes down to basic principles.
That is demand and supply.

Demand is the desire to buy, while supply is the desire to sell.
These two factors drive the prices of everything—from stocks, energy, gold, to crypto.
Regardless of what happens in the world, these principles always play a crucial role.

Let's start with demand.
This is the quantity of goods people want to buy at different prices.
If the price drops, buyers will want to buy more.
If the price rises, demand will decrease.
The simple reason is that when prices are lower, our money can buy more (income effect),
and we tend to compare it with similar products (substitution effect).

As for supply, it is the quantity that sellers want to offer for sale.
It is the opposite of demand.
When prices go up, sellers want to sell more because the profit is better.
When prices drop, sellers tend to hold back on selling—that's human nature.

When the demand curve and supply curve intersect, that point is called equilibrium.
At this point, price and quantity tend to stabilize.
If prices rise above this point,
sellers will offer more, but buyers will buy less, leading to excess supply, and prices will fall back.
Conversely, if prices fall below equilibrium,
buyers will want to buy more, but sellers will sell less, causing shortages, and prices will rise.

In financial markets, demand is influenced by many factors, such as economic conditions, interest rates, and investor confidence.
When interest rates are low, investors tend to buy more stocks because bank deposits offer low returns.
The amount of money in the system also affects demand—more money means higher buying interest.

Regarding supply, in the stock market, it depends on company policies, such as share buybacks (reducing supply) or issuing new shares (increasing supply).
New listings also increase supply, and stock exchange regulations have an impact too.

A clear example is the oil market.
In March, the Strait of Hormuz was closed due to tensions with Iran.
Oil supply sharply decreased—over 20% of the global supply vanished from the market.
Demand remained the same, so the result was a rapid spike in oil prices due to a shortage.
This is a true supply shock.

When it comes to stock trading, demand and supply are very important for fundamental analysis.
Rising stock prices indicate strong demand, while falling prices suggest strong supply.
But the real driver of demand is the forecasted profit of the company.
If investors expect growth, they are willing to pay higher prices.
If they expect losses, they hold back, and sellers lower prices.

In technical analysis, demand and supply are used through various tools, such as candlestick charts.
A green candlestick (close higher than open) indicates strong demand.
A red candlestick (close lower than open) indicates strong supply.
A doji (close near open) shows a balance between the two forces.

Trend analysis is also important.
If prices make new highs consistently, demand remains strong.
If prices make new lows, supply is dominant.
If prices move within a range, it indicates a balance between demand and supply.

Support and resistance levels are also related to demand and supply.
Support is where demand is hidden (buyers waiting to buy).
Resistance is where supply is hidden (sellers waiting to sell).

Demand Supply Zone techniques are popular for timing trades.
There are two main types: trading at reversal points and trend-following trades.

The Demand Zone Drop Base Rally (DBR) occurs when prices fall sharply, then move sideways.
When buying pressure returns strongly, prices break above the range and rally, attracting traders to buy at breakout points.

The Supply Zone Rally Base Drop (RBD) happens when prices rise, then consolidate.
When selling pressure returns, prices break below the range and drop, prompting traders to sell at breakout points.

Trend trading occurs when demand or supply remains strong in the same direction.
Rally Base Rally (RBR) indicates prices rising, consolidating, then rising further.
Drop Base Drop (DBD) indicates prices falling, consolidating, then falling further.

In summary, demand and supply are very simple concepts, but they are highly effective in understanding markets—whether stocks, oil, or other commodities.
Once you understand them, you can read the market better and make smarter investment decisions.
Of course, you need to deepen your understanding and apply it to real market prices to see the full picture.