Buying alt coins and taxable events?


I’ve heard that if I buy USDC on Coinbase for example, and then use this (stable coin) on a DEX e.g. Uniswap to swap for some alt coin… then this is a taxable event right ?

So if this happened during a particular tax year then what are the tax consequences ?

  • Is tax calculated on the USD appreciation value of the alt coin over the tax period since the time of the swap?
  • if that is true, then what happens in the subsequent tax year? is taxed owed on appreciation of the alt coin on that year also?
  • or is tax only applicable on any cashing out back to fiat ?

so confused… what is the easiest way to buy an alt coin to just hodl and only declare tax when cashed out ?