Prices of Bitcoin and Ethereum both fell sharply on Thursday, plunging by as much as 25% at one point amid worries that the cryptocurrencies may be set for a period of selling pressure as they entered technical levels that could offer strong resistance to upside momentum.

Bitcoin fell to a daily low of $2,210.00 on the U.S.-based GDAX exchange at one point, its lowest since May 30. It was last at $2,261.70 by 7:35AM ET (1135GMT), down $516.50, or about 18.6% on the day.

Other big exchanges such as Poloniex, Bitfinex and BitStamp also showed the cryptocurrency around the $2,200-level early Monday.

Goldman Sachs (NYSE:GS) chief technician Sheba Jafari recently warned clients that the bitcoin market may be heading for bearish territory, adding that they should consider the possibility of reinitiating positions after a pull back to between $2,440 and $1,915.

The move lower in bitcoin comes a few days after the digital currency hit a record high of $3,000 on Monday.

Meanwhile, Ethereum sank to a low of $285.01, before rebounding slightly to $290.74 in early New York morning trade, down $101.16, or around 25.8%.

Investors, however, remained optimistic that Ethereum would be the alternative cryptocurrency that usurps bitcoin as the largest and best capitalized blockchain – a phenomenon referred to as “the flippening”.