Fiat prices are taken as a weighted average market price against Bitcoin (BTC).
You can also change the weighted average market price for BTC depending on the exchange you choose in the settings to fetch the prices from there. The exchange price is available only for USD and EUR as those exchanges offer these currency pair markets. The choices are:
for EUR: weighted average, Bitstamp or Kraken
for USD: weighted average, Bitstamp, Kraken or Coinbase Pro
You can change your account currency in your account settings.
Coins and Assets:
Our price is an average price retrieved from several sources (like Blockchain.com, WorldCoinIndex, CoinMarketCap, etc) and weighted by volume of transactions on the exchanges.
This is important for the correct tax calculation since every transaction is taken into account with this asset value (Price * amount = asset value or cost basis) according the average price at the time of execution. Our system calculates the tax and gain based on these asset values (buy or/and sell price in every transaction).
They are sourced from www.xe.com. Trackable are for example Gold (XAU), Silver (XAG) and other precious metals with a price history available from this price source.