Shares of crypto miners and bitcoin-tracking companies climbed in premarket trading on Friday as the world's largest cryptocurrency extended a recent rally to touch a near 19-month high on improving risk appetite.

Bitcoin, up 2% at $38,410, has been gaining since October on optimism that a potential approval of a spot exchange-traded fund is likely to unleash more capital investments in the digital asset sector.

"Tailwinds have been gathering strength all year, especially in recent months, as spot ETF expectations build, the Binance uncertainty is resolved, and 2024's accelerated money printing becomes more inevitable," crypto-focused economist Noelle Acheson said, referring to the bitcoin rally.

Shares of bitcoin miners - whose profitability improves as bitcoin climbs - including Riot Platforms, Marathon Digital, Cipher Mining and TeraWulf rose between 2.4% and 4% in trading before the bell.

J.P.Morgan raised its price targets on Cipher Mining, CleanSpark, Iris Energy, Marathon Digital and Riot Platforms to reflect the rally in bitcoin.

Shares of bitcoin mining machine maker Canaan added nearly 4%.

The mining companies are also increasing production before bitcoin's "halving" event next year, when rewards for producing the tokens are cut in half.

Coinbase's shares rose 2.6% following the 62% jump in November that outperformed bitcoin's 11% climb even as the U.S. crypto exchange reported a decline in trading volume earlier in the month.

"Higher crypto prices should lead to a boost in transaction volume and transaction revenues for Coinbase as we enter 2024," said CFRA Research analyst Michael Elliott.

However, Elliott cautioned the crypto exchange faces both legal challenges and new regulations that are likely to take time to play out and will continue to result in volatility for the stock.

The ETF approval bets have helped counter latest concerns after Changpeng Zhao, the founder of the world's largest crypto exchange, stepped down and pleaded guilty to breaking U.S. anti-money laundering laws.

Among other premarket gainers were U.S. software developer and bitcoin investor Microstrategy, up nearly 5%, and ProShares Bitcoin Strategy ETF, which added 2%.

(Reporting by Medha Singh in Bengaluru; Editing by Sriraj Kalluvila)