Any gain/loss due to exchange rate , is not reportable/ taxable, especially for personal assets.
The only area where there may be effects is for FBAR and FATCA --- e.g. if you have a foreign bank account ( owned / signature authority only), the same foreign currency amount may require filing form 114 depending on exchange rate on the last day of the year.
What are you trying to achieve? Are you a US citizen/resident/resident for tax purposes?