A Checklist for Before You Buy a Stock: Questions to Answer in Writing

Alpha Sentinel is a software platform, not a registered investment adviser. This article is educational, not investment advice. Full disclaimer at the end of this post.

A surgeon is in the scrub room before an afternoon case when a colleague mentions a stock he just bought. By the time the case is over, the surgeon has talked himself into the same idea without writing down a single reason. The best defense against that kind of impulse is a written checklist you answer before any purchase. It moves the decision from the moment of excitement to a calm moment on paper, and it leaves a record of what you believed and why. Here are the questions worth answering in writing, along with how to answer them without a research team.

Key Takeaways

• Writing answers down forces you to separate reasons from excitement and leaves a record you can review later.
• The most important question is what you expect to happen, and what would show you were wrong.
• A checklist cannot make a decision good, but it prevents decisions made without thought.
• Keep the list short enough that you will actually use it every time.

1. What Does This Company Do, and How Does It Make Money?

Start with a plain-language description of the business, in two or three sentences, without jargon. What does it sell, to whom, and how does money come in? If you cannot write that without copying from a website, you do not yet understand the company well enough to own it.

A useful test is to explain it as if to a colleague who has never heard of it. Many investors discover at this step that they know the stock's story, the headline or the narrative, but not the business. The company's annual report, filed with the SEC as a Form 10-K, contains a business description in its first section that is written for exactly this purpose and can be read on the SEC's EDGAR database.

Also write down how the company earns its profit: one product line or several, one big customer or many, recurring revenue or one-time sales. These details shape how risky the business is and what could go wrong.

2. What Is My Reason, and What Would Prove It Wrong?

Write down in a sentence or two why you want to own this stock, as specifically as you can. "It seems strong" is not a reason. "I believe demand for its main product will grow because of a change in how customers buy it" is a reason, and it can be checked.

Then write the more important line: what would prove you wrong? Name two or three observable facts, such as a loss of a major customer, a sustained decline in revenue or a rise in debt, that would mean your reasoning no longer holds.

This pair of questions turns a vague feeling into a testable statement. It is also the basis of a later review: you can compare what happened to what you wrote, with no room for revisionist memory.

3. What Is Already Reflected in the Price?

A good business is not automatically a good purchase, because the price already reflects what many investors expect. Ask what the price implies. Is the company valued at a high multiple of its earnings relative to its own history and to similar businesses? What growth would be needed to justify that price, and is it plausible?

You do not need a sophisticated model. Compare a few simple measures, such as the price relative to earnings or to sales, against the company's past range and against peers. If the stock trades well above both, you are paying for a lot of future success, and the margin for disappointment is thin.

Write down what you notice and what you are unsure about. Uncertainty you have named is easier to manage than uncertainty you have ignored.

4. What Could Go Wrong, and How Much Could I Lose?

List the main risks in specific terms. Company-specific risks might include heavy debt, dependence on one customer, or a pending legal matter. Industry risks might include regulation or technological change. Market-wide risks include a broad decline that pulls most stocks down together. The risk factors section of the company's 10-K lists risks management itself considers material, and it is a good place to start.

Then translate risk into dollars, as an illustrative exercise. If the position fell by a third, what would that mean for your total portfolio, and could you accept it without changing your plans?

Finally, check how this holding relates to what you already own. A new position in the same sector as your largest holdings adds to concentration, even if the company is different. Concentration is a subject on which a qualified advisor or tax professional can help; working with advisors and self-directing are both legitimate approaches.

5. How Large Will the Position Be, and What Is the Plan?

Decide the size before you act, as a percentage of your portfolio, and write it down. The right cap depends on your circumstances; the point is to choose it in advance.

Decide also how you will review the position. Will you reconsider it on a set schedule, or when a specific event occurs, such as an earnings release? Will you add to it only under defined conditions? A plan written before purchase is easier to follow than one invented while the price is moving.

Consider the practical details too: which account will hold it, since the tax treatment differs between taxable and retirement accounts, and what order type you will use. These are small details that cost very little to settle in advance and can cost a lot to improvise.

An Illustrative Walk-Through

The following is an example only, not a result or a recommendation. Imagine an attorney who keeps a one-page template with the five questions above. On a Sunday afternoon she considers a company she has heard about from a colleague. She spends about forty minutes with the company's latest annual report, writing two sentences about the business, one sentence of reasoning and three observable facts that would prove her wrong.

She notes that the price is high relative to the company's own history, lists two company risks from the filing, and writes down how large the position would be as a share of her portfolio and what a one-third decline would mean in dollars. She decides she needs another week to think, saves the page and sets a reminder. The checklist did not tell her what to do. It slowed the decision enough that she made it on purpose.

Frequently Asked Questions

What should I research before investing in a stock?

At minimum, understand what the company does, how it makes money, what its main risks are and what the price implies. The company's annual report on SEC EDGAR covers the first three, and a few simple comparisons cover the last.

How much time should stock research take?

Even a thorough first pass can be done in an hour or two for a single company if you focus on the business description, risk factors and a few valuation comparisons. A short, repeatable process beats an exhaustive one you will not repeat.

Should I write down why I am making an investment?

Yes, because a written reason can be tested later against what actually happened. It also reveals when you have no clear reason at all, which is useful to know before you commit money.

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