Thank you, you were right. The reason was: I didn’t notice that when I imported US securities, the currency of all securities was set as account currency (i.e., GBP rather than USD). Once I set security currency to USD and an appropriate exchange rate in the buy transaction, account value started behaving as expected.
However, that led me to the next stumbling block. I’m now getting an error “Exchange rate of gross value is missing (transaction currency GBP and security currency USD)” when trying to import transactions (transactions use GBP as the currency as all USD->GBP conversions are done by my British brokerage). I found a link to this post from 2021, where you seem to say that correctly importing transactions in one currency where underlying security is quoted in another currency is not possible and have to be done manually via UI.
https://forum.portfolio-performance.info/t/exchange-rate-of-gross-value-is-missing-when-importing-csv-transactions-with-currency-conversions/20633
Do you know if that is still the case in 2024, or am I missing something about the import process? (I thought the GrossAmountCurrency import column was supposed to handle this exact case?)