Cryptocurrency markets are feeling the pressure from an extended downturn on Wednesday, September 12, with Bitcoin (BTC) losing 2.5 percent and Ethereum (ETH) hitting its lowest levels since May 2017.

Data from Cointelegraph’s price tracker and Coin360 confirms the lackluster picture across cryptoassets continuing another day, with all of the top twenty coins — with the exception of Dogecoin (DOGE) — in the red.

Market visualization from Coin360

Bitcoin had climbed to almost $7,400 last week before turmoil hit markets again, prices tumbling over claims Goldman Sachs had shelved its crypto trading plans, something officials have since dismissed as “fake news.”

Regulatory pressure also continues, with U.S. authorities ordering a ten-day halt of two exchange-traded notes (ETNs) over the weekend.

The combined effect has meant BTC/USD was tending towards $6,200 at press time, support nonetheless holding at around $6,251 to prevent a deeper slide below the $6,000 barrier.

Bitcoin’s 7-day price chart. Source: Cointelegraph's Bitcoin Price Index

For Ethereum, the outlook appears bleaker.

Recent comments by co-founder Vitalik Buterin about the lack of growth perspectives in blockchain appeared to exacerbate ETH’s descent to 2018 lows.

Buterin has since denied claims he is a “pessimist” about the outlook for cryptocurrency, arguing media publications had “spun” his words.

Nonetheless, ETH has faced a bearish tide for several months, with industry research from Tetras Capital in July warning the asset faced a prolonged cooling-off period after the intense growth it saw from the 2017 Initial Coin Offering (ICO) phenomenon.

At press time, ETH/USD traded around $172, down almost 11 percent on the day. Ethereum last saw this price point in July of 2017.

Ethereum price chart. Source: Cointelegraph's Ethereum Price Index

For other major altcoins, losses came as a result of Bitcoin’s downturn, Dash (DASH) and Litecoin (LTC), and Bitcoin Cash (BCH) all almost matching ETH’s minus 11 percent performance. Altcoin Cardano (ADA) went further, dropping around 14 percent.

The suppression of altcoin prices had meant Bitcoin’s overall market dominance has reached multi-month highs nearing 58 percent, according to data from CoinMarketCap. Bitcoin last achieved that market share in December, when prices hit all-time highs around $20,000.