Most explanations of investing skip the part where money actually changes hands. Here is that part, start to finish, with nothing assumed.
You Need a Brokerage Account
You cannot walk up to a company and ask for a share. Shares change hands on an exchange, and only members of the exchange trade there directly. A brokerage is a firm that is a member and will act on your behalf.
Opening an account works much like opening a bank account: identity documents, a Social Security number in the US, some questions about your income and experience that regulators require, and a link to a bank account for moving money in.
The account is a container. Putting money into it does not purchase anything. That catches out more first-timers than anything else here: the cash sits in the account until an order is placed.
Two things that hold across the major US brokers today:
- Trading US stocks costs no commission at most large retail brokers. It was not always this way, and other fees still exist, so read the fee schedule your own broker publishes rather than trusting a number written anywhere else, this page included.
- Your shares are recorded in the broker's name on your behalf, which the industry calls street name. You remain the beneficial owner. It is a bookkeeping arrangement that makes trading fast, not a claim on your shares.
What Happens When You Press the Button
You type a ticker, a number of shares, and confirm. From your side it takes a second. Underneath, a chain runs:
- Your broker receives the order and checks the money is there.
- The order is routed to a venue where buyers and sellers meet, an exchange or a market maker.
- It is matched against someone going the other way.
- The trade is reported, and the shares appear in your account.
The person on the other side is a stranger with no idea who you are. There is no approval step and no negotiation. If the price is agreed, it is done.
Settlement: When It Is Really Yours
The trade appears instantly. The paperwork behind it finishes the next business day. In the US, stock trades settle one business day after the trade, a rule known as T+1 since it shortened from two days in May 2024.
For a long-term investor this is close to invisible. It matters mostly for cash timing: selling shares makes the proceeds fully available only after settlement, so money from a Monday sale is not necessarily spendable on Monday.
Order Types, Without the Jargon
Every broker offers at least two ways to place an order, and the difference is what you are prioritizing.
Market order: speed over price. The instruction is "fill this now, at whatever the going rate is." It executes almost immediately during market hours. The catch is that the price you get is the price available at that instant, which may differ from the number that was on your screen a second earlier. On a large, heavily traded company the gap is usually pennies. On a thinly traded one it can be much wider.
Limit order: price over speed. The instruction is "no worse than this price." A limit order set at $50 will not fill above $50. The catch is the mirror image of the other one: if the price never comes to your number, nothing happens at all.
Two more show up in most apps.
Stop order. A dormant instruction that wakes up if the price crosses a level you set. People use them to automate an exit. They are not a safety net: in a fast-moving market the order becomes live and then fills at whatever is available, which can be well past the level that triggered it.
Good-til-canceled. Not a type of order but a duration. A day order expires at the close. A good-til-canceled order waits, usually for a few months depending on the broker, until it fills or is canceled.
Market Hours
The US exchanges are open 9:30am to 4:00pm Eastern, Monday to Friday, minus market holidays. Most brokers also offer extended hours before and after that window, where far fewer people are trading and the gap between what buyers offer and what sellers ask is wider.
An order placed at 9pm on a Sunday does not vanish. It queues, and it goes to work when the market opens.
The Honest Summary
The mechanics are the easy part. It is a form with three fields, and the industry has spent twenty years making it frictionless.
The hard part is everything the form does not ask: whether you understand the business, what you expect from it, and what you will do when it moves. The rest of this course is about that.
This content is for informational purposes only and does not constitute financial advice.