If you bought the stock for $100, and now it’s worth $200, and you sell $10 worth to buy a sandwich, you have $5 of income to be reported.
> To reduce the number of currency conversions required, the tax code uses the standard of FAS 52, which is the Financial Accounting Standards Board standard for foreign currency conversions. This allows the business to record most of its transactions in terms of its functional currency (FC), which is the currency that is generally used by businesses in the locale of the foreign unit or entity. Generally, under FAS 52, fluctuations in currency rates do not have to be accounted for unless the fluctuations change the cash flow for the business. In most transactions of a foreign business unit in a foreign country, cash flows are not affected by currency fluctuations. However, transactions between the parent company and its foreign subsidiary will result in a change of cash flow. As a consequence, gain or loss on the currency exchange will have to be included when calculating net income.
https://thismatter.com/money/tax/foreign-currency-transactio...
> do not have to be accounted for unless the fluctuations change the cash flow for the business
If there is a change in value then it needs to be reported. It's the same concept as if you were forex trading.
However, this is one of those things where the government isn't going to come knocking your door down for since it's petty cash.
https://www.irs.gov/businesses/small-businesses-self-employe...