Bitcoin's (BTC) percentage share in the crypto market has risen to nearly 50% in the aftermath of the last week's altcoin market rout.

On June 13, the Bitcoin Dominance Index (BTC.D), which tracks BTC's weight against other cryptocurrencies, reached 49.29%, slightly down from its two-year highs of 49.66% seen earlier this week. 

BTC.D daily price chart. Source: TradingView

BTC not an "unregistered security" 

The surge in Bitcoin dominance comes after the United States' Securities and Exchange Commission's (SEC) lawsuit against the crypto exchanges Binance and Coinbase. In its court filings, the commission accused many leading altcoins, including Cardano (ADA) and Solana (SOL), of being "unregistered securities."

Related: SEC’s Gensler says BTC, ETH ‘not securities’ in a newly surfaced video

Bitcoin's market share typically rises during high market stress, given that traders view it as the least volatile, non-stablecoin crypto asset than most cryptocurrencies. For instance, at the height of banking crisis in March 2023, Bitcoin's dominance versus altcoins had also rebounded to 50%.