A copy of bitcoin standing on PC motherboard is seen in this illustration picture, October 26, 2017. REUTERS/Dado Ruvic

LONDON (Reuters) - Bitcoin hit a new record high on Monday after smashing through the $8,000 (£6,043.6) level for the first time over the weekend, marking an almost 50 percent climb in just eight days.

The new high came after leading U.S. payments company Square Inc said late last week that it had started allowing select customers to buy and sell bitcoins on its Cash app.

Bitcoin traded as high as $8,197.81 on the Luxembourg-based Bitstamp exchange, up over 2 percent on the day and around 48 percent up since dipping to $5,555 on Nov. 12.

An eye-watering eightfold increase in the value of the volatile cryptocurrency since the start of the year has led to muliple warnings that the market is in a bubble, and institutional investors are broadly staying away.

Retail investors, however, as well as some hedge funds and family offices, are piling into the market. The “market cap” of all cryptocurrencies hit an all-time high of over $242 billion on Monday, according to trade website Coinmarketcap.