Bitcoin tumbles 7%, pushing it near $50,000 threshold as retail-investor interest wanes

• Bitcoin slid by about 7% on Thursday, pushing it near the $50,000 threshold, well off recent record highs.
• Analysts said the expiration of more than $5 billion in bitcoin options contracts may be causing volatility.
• The price of ether also fell, along with the Binance coin, Polkadot, Cardano's ADA, and Ripple's XRP.

Bitcoin fell on Thursday by as much as 6.7%, to $50,440.17, as retail-investor interest slipped and the options market triggered volatility.

Bitcoin is down by about 17% from the record high of $61,742.41 reached earlier in March. But it's still up roughly 672% over the past year.

Analysts suggested a reason for bitcoin's fall was that more than $5 billion worth of options expire on Friday, adding to volatility as investors close out their positions.

Options are contracts that let investors bet on which way the price will go without having to trade the digital currency itself.

The unwinding of contracts and some investors trying to push the price lower to make money from their bets against bitcoin in the options market "have led to spot-selling pressure into quarter-end," Shane Ai, the head of research and development at the crypto exchange Bybit, told Insider.

He also said that Tesla's announcement on Wednesday about accepting bitcoin as payment - after which the bitcoin price spiked above $57,000 - had caused some investors to sell their coins and make a profit.

After bitcoin's meteoric rise, a growing number of investors have predicted a fall.

Ari Paul, the founder of BlockTower Capital, tweeted on Wednesday that bitcoin falling back to about $40,000 "is plausible and I'll likely be buying there." He said there were "too many people positioned for immediate upside continuation."

Bobby Lee, the founder of the crypto exchange BTCC, told CNBC on Monday that bitcoin could reach $300,000 before the "bubble" pops. "People should be aware that it could fall as much as 80% to 90% of its value from the all-time peak," he said.

Ether, the second-biggest cryptocurrency, also slid on Thursday by about 6%, to $1,614. The Binance coin, Polkadot, Cardano's ADA token, and Ripple's XRP were down by 3% to 13%.

Justin d'Anethan, the head of exchange sales at the Nasdaq-listed crypto firm Diginex, told Insider that the recent sell-off in the stock market had likely spread to cryptocurrencies too.

"With concerns around the economic recovery, doubts about recent employment data, and infection rates ticking up, investors seem to have transferred some of their equities holdings into cash. Crypto investors likely did the same," he said.

However, many bitcoin advocates have pointed to growing institutional interest as a reason bitcoin is unlikely to crash as it has in the past. Visa, Morgan Stanley, and JPMorgan are some of the latest big names to get involved.