Bitcoin surpassed $20,000 and was poised for its best day in six weeks on Friday, as the U.S. dollar sank broadly and markets found reasons to be upbeat after a gloomy week.

Bitcoin, the largest cryptocurrency by market capitalization, climbed more than 7% to a two-week high of $20,796. Ether, the second-largest cryptocurrency, surged 5% to reach a two-week high of $1,717. On Wednesday, Bitcoin had fallen as low as $18,540.

Market participants stated that there was no specific catalyst for the gains, other than a broad positive sentiment across asset classes on Friday, led by a decline in the safe-haven dollar and a rise in Chinese stocks.

If cryptocurrencies can maintain their gains until Sunday's close, Bitcoin might record its second consecutive weekly increase and its greatest week in about a month. read further

Ether's weekend volatility may be exacerbated by an impending software upgrade known as the "merge" that is due between September 10 and 20, with the precise date undetermined.

The transition is expected to drastically alter how transactions are processed and reduce energy use. Several exchanges intend to suspend deposits and withdrawals during the update.