6 US-stock research checks for UK investors

1. Confirm the issuer, exchange and share class#

Record the legal company name and instrument, not just the brand. Ordinary shares, preferred shares and depositary receipts can carry different economic or voting rights. Use the issuer's verified investor-relations materials and SEC filings to establish what the US-listed security actually represents.

2. Check whether an ADR represents multiple shares#

An American depositary receipt (ADR) can represent one underlying share, several shares or a fraction. The SEC's ADR bulletin explains this structure. Check that ratio before comparing its price with an ordinary share; otherwise you may mistake a different number of shares for a discount. Read the deposit agreement and applicable fees too.

3. Separate trading currency from business exposure#

Check which currencies the company earns revenue and pays costs in, as well as the quote currency and the currency you use to measure your own results. Those exposures can differ. The SEC's international-investing guide explains currency and other cross-border risks that remain after you convert a share price.

4. Align financial periods and accounting labels#

Two “2025” reports can end in different months. Compare actual period boundaries and note whether the issuer uses US GAAP or another accounting framework. Foreign private issuers may file an annual 20-F and furnish information on 6-K rather than follow the domestic 10-Q pattern. Do not infer missing results from the wrong form filter.

5. Check the market-data timestamp#

Write down whether you are using a regular-session close, an intraday quote or an after-hours price. The UK and US change daylight-saving time on different schedules, so a remembered time conversion can be wrong around those transitions. For a material calculation, preserve the actual timestamp and timezone rather than writing “today's price”.

6. Verify access, fees and tax questions separately#

A research tool and a brokerage serve different jobs. Before assuming you can hold a security in your account, ask the broker about availability, account eligibility, charges and currency conversion. Check ISA eligibility and tax questions separately with the broker or a qualified professional; a company-research page cannot settle them.

A fictional ratio example#

Suppose one ADR represents two ordinary shares. Each ordinary share is quoted at £20, and the illustrative exchange rate is $1.25 per £1. The equivalent underlying value is 2 × £20 × 1.25 = $50 per ADR before fees and market differences. Comparing the ADR with $25 would forget half of the underlying shares.

After correcting the ratio in this hypothetical calculation, check whether trading times and fees explain any remaining gap. Keep the ratio source and exchange-rate date with your calculation. See seven valuation mistakes for other comparison errors.