Step one: understand what over-the-counter means
Over-the-counter means the trade happens between parties through a dealer network rather than on a centralized exchange order book. Securities trade this way for many reasons: a company too small for listing standards, a foreign company whose primary listing is elsewhere, a business that deregistered, or one that never registered at all. The venue says where trading occurs, not what the company is worth.
The practical consequence is that there is no single official price and no exchange rulebook governing the issuer. Quotes are published by market makers through a quotation system, and the obligations attached to the security come from securities law and the quotation system's own tier requirements rather than from listing standards.
Step two: read the tier before anything else
The tiers are disclosure regimes. The top tier requires current audited financial reporting to a recognized standard; the middle tier requires current disclosure but with lighter requirements; the bottom tier has no current-information requirement at all and includes shells, delinquent filers and companies about which almost nothing recent is public.
Nothing about a tier is a quality judgment, and reading it as one is the most common mistake in this corner of the market. A substantial foreign company with a full home listing can appear in the same venue as a dormant shell. The tier tells you what you are entitled to know before you trade, which is a genuinely different and more useful fact.
The one-line versionA tier is an answer to "what will I be able to read about this company?" It is not an answer to "is this company sound?" Anyone who conflates the two will eventually buy something they could not have researched and conclude the market was rigged.
Step three: expect the quote to behave differently
On a heavily traded listed share the bid-ask spread is often a cent. Off-exchange it can be several percent of the price, and on the thinnest names the two sides of the quote can be far apart with no depth behind either. Crossing that spread is a real, immediate cost paid at the moment of entry, and it has to be paid again on the way out.
Two mechanical habits follow. First, use limit orders: a market order into a wide, thin quote can execute at a price you would not have accepted if asked. Second, check the size behind the quote, not just its level; a tempting price for 100 shares says nothing about what 5,000 would cost. Both of these are why the step-by-step answer to how to trade OTC stocks always includes "more slowly".
Position size against volume, before entry
The single most useful arithmetic in this market takes one division: intended position size over average daily volume. At a few percent, exiting is an ordinary decision. At a substantial fraction, exiting means becoming most of the day's trading in that security, and the price you achieve will reflect that rather than any view about the business.
This is the calculation that turns a general warning about liquidity into a specific limit, and it belongs before entry rather than during an attempt to leave. At that point the only variables left are how much and how fast, and both of them work against you.
Foreign companies, and why the venue is not the verdict
A substantial share of off-exchange volume is in the securities of large foreign companies with full primary listings on their home exchanges. Such a company may publish audited accounts to its own national standard, be covered by analysts across Europe or Asia, and still appear in the same venue as a dormant shell, because trading off-exchange in the US is a distribution arrangement rather than a statement about the issuer.
This is the clearest single argument for reading the tier and the filing date instead of the venue. The venue tells you how the security reaches a US broker. The tier tells you what current information you are entitled to before trading it. Those are different questions, and only the second one has any bearing on whether ordinary analysis is even possible.
Step four: know which risks the tier leaves standing
Information risk is the first. In the lowest tier there may be no current financial statements at all, so ordinary analysis is not merely harder; the inputs do not exist. Any screen or score applied to such a company is running on stale or absent data.
Liquidity risk is the second, and it is the one that surprises holders rather than buyers. Entering a thin position is usually possible; exiting one at a comparable price frequently is not. Position size relative to typical daily volume is the number that decides this, and it should be considered before entry rather than at exit.
Promotion risk is the third and the most specific to this venue. Paid promotional campaigns dressed as research have historically concentrated on thinly traded off-exchange securities, precisely because a small amount of buying moves the price. Compensated promotional material is required to disclose the compensation, and that disclosure is usually present, small, and at the bottom of the page. Reading it first is the single most useful habit anyone can bring to this market.
The rule that decides whether a quote may be published at all
Broker-dealers may only publish quotations for a security when current issuer information is available: the requirement generally referred to by its rule number, 15c2-11. In practice this is why the tiers exist as they do, and why a company that stops filing eventually loses its public quotations: not because anyone judged it, but because the condition for quoting it stopped being met.
The visible effect for a reader is a security moving to an expert-market or unsolicited-quote state, where quotes are no longer displayed publicly and trading becomes far harder to price and to exit. A holder can find the position effectively unquotable without any trading halt having occurred. Checking the date of the most recent filing before entering is therefore not diligence about the business; it is diligence about whether the security will still have a visible market next year.
Halts, designations and what they change
Two different things stop or mark trading and they are often confused. A regulatory halt suspends trading in a security entirely, for a defined period, and it resumes under stated conditions. A designation, of which the skull-and-crossbones caveat-emptor marking is the best known, is a persistent public warning attached to the security by the quotation venue, typically over promotion, spam or a serious public-interest concern, and it can restrict how brokers may accept orders in it.
Both are published, both are visible before you trade, and neither is a judgment about the underlying business in the way readers assume. A halt can precede good news as easily as bad. A designation, by contrast, is the venue saying something specific about the security's trading conduct, and it is the one signal in this market that is worth treating as close to disqualifying; it exists precisely because promotion campaigns concentrate here.
Step five: how to trade OTC stocks once the checks are done
Check the tier and the most recent filing date. Read the quote and the size behind it. Decide the maximum price you will accept and enter it as a limit. Size the position against average daily volume rather than against your conviction. Expect partial fills, and expect a wider spread on the way out than the one you crossed on the way in.
None of that is exotic; knowing how to trade OTC stocks step by step is the ordinary discipline of a market with less information and less depth. The mechanics of ownership, settlement and clearing are the same as anywhere else, and settlement is still T+1. It is the information and liquidity environment, not the plumbing, that makes trading OTC stocks a different exercise.