Have you ever wondered why the price we pay when buying stocks differs from what we see in the app?

This is because of something called the Bid-Offer Spread that operates behind the scenes, and this matter is more important than we often think.

In the stock market, Bid is the highest price a buyer is willing to pay for a security, while Offer is the lowest price a seller is willing to accept.
This difference is not just a simple mathematical number but reflects the changing supply and demand every second.
When more people buy, the Bid price rises, but if more people are selling, both Bid and Offer prices tend to move downward.

For securities sellers, the Bid is important because it indicates how much people are willing to pay for our stock.
The Offer is the amount the seller wants.
If the Offer is much higher than the Bid, it indicates low liquidity and difficulty in executing transactions.
However, if the Spread is narrow, it shows a lively market.

Understanding the pattern of Bid-Offer changes helps a lot.
If the Bid is narrow, the Offer is also narrow, indicating a trend but still lacking volume because people haven't traded much yet.
Observe closely: when the Bid is narrow but the Offer is wide, buyers are gradually entering.
When the Bid is wide and the Offer is narrow, it often signals the end of a trend.
And if both Bid and Offer are wide, that’s when the volume peaks.

A simple example: Suppose we want to buy Security A at $173.
We think it will cost us $1,730 for 10 shares, but after payment, it turns out to be $1,731.
Surprised?
That’s because the $173 price is the latest traded price, but the actual price we receive is the Offer at $173.10.
This difference is the Spread, which becomes profit for the broker.

The advantage of understanding the Bid-Offer is that it helps us choose better times to enter and exit the market.
When the Offer is low and close to the Bid, the market has good liquidity, reducing trading costs.
The downside is that a wide Spread increases our costs, especially for small-cap stocks or securities with low trading volume.

Large securities like top-tier stocks have almost invisible narrow Spreads because there are many Bids and Offers every second.
But other securities, such as small-cap stocks or some bonds, may have a Spread that is a significant percentage of the price.
Knowing this helps investors calculate the true cost of their investments more accurately.

In summary, the Bid-Offer Spread should not be overlooked because it is part of a smart trading strategy.
When we understand that the Offer is the price we pay and the Bid is the price we receive when selling, we can plan our market entries and exits more effectively and reduce unnecessary costs.