During market volatility, the price ratio between different cryptocurrencies fluctuates significantly. For example, when Bitcoin's price soars relative to Ethereum, the BTC - ETH ratio increases. This can be due to various factors like regulatory news affecting one coin more than another or technological upgrades in a particular cryptocurrency. For investment portfolios, these ratio changes imply the need for periodic rebalancing. If an investor's portfolio has a set ratio of different cryptos, shifts in price ratios may prompt selling of over - performing coins and buying under - performing ones to maintain the desired risk - return balance.