Bitcoin heads for worst monthly slide since December 2013

Cryptocurrencies are extending losses with Bitcoin headed for its worst monthly slide since December 2013 on the last day of January trading as US regulators ramp up their scrutiny of one of the world’s largest digital currency exchanges while Facebook Inc. is banning ads tied to the industry.

Bitcoin is down about 31% this month, trading at $9,817 as of 10:20 a.m. in Hong Kong, according to composite pricing compiled by Bloomberg. Rival coins Ripple, Ethereum and Litecoin are also down at least 2%, the data show.

“The regulatory oversight and the clampdown is really coming to the fore right now,” Stephen Innes, head of trading for Asia Pacific at Oanda, said by phone from Singapore. “I don’t think we’ve seen the last of it.”

The US Commodity Futures Trading Commission sent subpoenas on Dec. 6 to cryptocurrency trading venue Bitfinex and Tether, a company that issues a widely traded coin it claims to be pegged to the dollar, according to a person familiar with the matter who asked not to be identified discussing private information. The firms share the same chief executive officer.

Facebook, meanwhile, will ban ads on its social network promoting digital currencies, initial coin offerings and binary options, warning they’re “frequently associated with misleading or deceptive promotional practices.”

Cryptocurrencies are still reeling after a record $500 million heist from Japanese exchange Coincheck on Jan. 26, further intensifying calls for increased oversight in global trading hotbeds such as South Korea.