Small reads.
Big “aha” moments.

Yes. If a data system fails to match the same security across an operational transition, it can show missing values, duplicated holdings or a discontinuity. Reconcile the exchange record and security identity before treating that apparent jump as an investment return.

Not always. Holdings data can show what changed while leaving the reason unresolved. Index eligibility, corporate actions, maturities, cash flows, price movement and discretionary decisions can produce different changes. A conviction score should not treat every observed sale as the same kind of manager judgement.

Not generally, because the portfolio total changes too. Recalculate the stock value divided by the new total, including other holdings on the same basis. A successful price move can increase concentration without a new purchase, but doubling the old percentage ignores the denominator change.

Look at the bid–ask spread, traded value, depth available for your quantity and likely execution cost over several observations. A large volume number on one event day does not establish that an ordinary later sale can occur near the displayed price.

No. Broader potential access can be relevant, but actual liquidity must be observed. Spreads, traded value, order-book depth and execution cost determine the practical experience. A new segment label does not guarantee a buyer for a large position at the displayed price.

No. A proposed move describes an intended or pending transition. Completion and the actual trading arrangements need the relevant exchange communication. An index-effective date cannot automatically be used as proof that every operational migration step has already finished.

Yes. If a company moves outside the listing universe represented by an SME benchmark, membership can change for that reason. Such an exclusion is different from an automatic allegation of default or misconduct. Read the stated reason and whether the migration is proposed or completed.