Asked on 27 May 2019
Coversion rates between currencies will fluctuate.
If your risk profile is not comfortable with it, you may want to consider keeping it in SGD instead.
FX investment tend to have more volatility as either currencies can rise or fall. I myself, to not do fx investment due to this nature.
You may want to consider your desired outcome and put it against the risks to determine if you want to stay invested or not.
Are you able to use the USD to generate better returns elsewhere like in the US market? If so, better to keep it in this currency. The reverse is true as well. If you can generate better returns in SGD terms, convert and do so.
Like what Clarence has mentioned, there's fluctuations in currencies so the exchange rate will differ on a day to day basis.