I'm Singapore planning to move to US in 2-3 months. I have some ESPP shares(US Company) that I would like to keep for another year or more. If I sell these shares after moving to US will it be taxed as an Income? As Singapore don't have any sort capital gains tax would it be advisable to sell it now to avoid any taxation?
Yes, it will be taxed as capital gains. If you have significant appreciation on these stocks, it may make sense to realize the gains prior to moving to the US, and repurchase if you want to keep holding the stocks.