Buying a stock on a phone can take only a few seconds. The simplicity of that screen hides an enormous financial infrastructure operating behind it. When someone taps buy, the money does not travel directly from that person's bank account to the company whose logo appears on the screen. For most everyday stock trades, the company itself is not a participant in the transaction at all.
Understanding why requires separating the primary market from the secondary market.
When companies first sell shares
A company can raise capital by issuing ownership interests to investors.
When shares are sold by the company as part of a new securities offering, money can flow to the issuer. An initial public offering, or IPO, is the most familiar example of a private company offering shares to public investors.
Once those shares are trading publicly, investors can buy and sell them from one another in the secondary market.
If you purchase shares of a large public company through a brokerage account on a normal trading day, your purchase usually does not send new capital to that company. You are acquiring shares that already exist from another market participant.
The stock exchange helps create an organized market in which those transactions can occur.
What your broker actually does
An online brokerage account can create the impression that an investor is directly connected to an exchange.
Investor.gov explains that this generally is not how execution works. When an investor submits an order, the broker receives it and decides where to route it for execution. Depending on the security and the broker, that destination might be an exchange, a market maker, an electronic communications network, or another execution venue.
Market makers play an important role in this system. They stand ready to buy or sell securities at quoted prices, helping markets remain liquid.
A stock usually has a bid price and an ask price.
The bid represents a price at which someone is willing to buy. The ask reflects a price at which someone is willing to sell. The difference between the two is called the bid-ask spread.
Highly traded stocks often have very narrow spreads because many buyers and sellers are competing. Less liquid securities may have wider spreads.
Why the price keeps changing
A stock price is constantly being negotiated through orders submitted by market participants.
Suppose buyers become more willing to pay higher prices for a company's shares after an unexpectedly strong earnings report. Existing sell orders may be filled, and new trades can occur at progressively higher prices.
If investors become more eager to sell, the process can move in the opposite direction.
This is why a stock does not have one permanent correct price displayed by an authority. Market prices emerge from continuous interaction among buyers and sellers using available information and expectations about the future.
Those expectations can change quickly.
A company can report growing profits and still see its stock fall if investors had expected even stronger results. Markets often respond to the difference between reality and prior expectations.
Market orders and limit orders are different
One detail that new investors sometimes overlook is that an order to buy a stock can contain different instructions.
A market order asks for execution immediately at the best available price. Investor.gov explains that a market order generally ensures execution when a market is available, while the exact execution price is not guaranteed.
That distinction becomes important when prices are moving rapidly.
A limit order allows an investor to specify the maximum price they are willing to pay when buying, or the minimum price they are willing to accept when selling. The trade will only execute if the market reaches an acceptable price, which means execution itself is no longer guaranteed.
The choice changes what the investor is prioritizing: speed of execution or control over price.
A completed trade still has to settle
Execution and settlement are related, although they are different stages.
Execution occurs when a buyer and seller are matched and a trade takes place.
Settlement is the later legal and financial transfer of the securities and cash.
Since May 28, 2024, the standard settlement cycle for most U.S. broker-dealer securities transactions has been T+1. This means settlement generally occurs one business day after the trade date for covered transactions such as stocks and ETFs.
The shortened settlement cycle matters because modern markets involve enormous volumes of transactions. Clearing agencies and depositories help ensure that obligations are properly processed between market participants. The SEC identifies broker-dealers and clearing agencies among the institutions that support U.S. securities markets.
So what are you buying?
A share of common stock represents an ownership interest in a corporation.
That ownership may provide voting rights and can allow shareholders to benefit if the company's value rises. Some companies distribute part of their earnings through dividends, although dividends are never guaranteed simply because a company has shareholders.
The stock market gives owners a mechanism for transferring those shares to other investors.
That liquidity is one of the reasons public equity markets matter so much to the economy. Investors are generally more willing to provide capital when there is an established system for eventually selling an investment.
The next time a stock purchase takes two seconds on a phone, it is worth remembering how much is happening underneath the interface. A broker routes the order, a trading venue or market participant executes it, clearing infrastructure processes the transaction, and settlement completes the transfer.
The app makes the process look simple because the market underneath it is highly organized.
Sources
- U.S. Securities and Exchange Commission, Investor.gov, Executing an Order.
- Investor.gov, Types of Orders.
- Investor.gov, New T+1 Settlement Cycle: What Investors Need to Know.
- SEC, Shortening the Securities Transaction Settlement Cycle.