FRANKFURT — Deutsche Bank (DB.N) has joined the ranks of those warning about the virtual currency Bitcoin as an investment.

"I would simply not recommend this to the everyday investor," Ulrich Stephan, chief strategist at Germany's largest lender, said on Wednesday.

Stephan said that fluctuations are too great and regulation too scant. He noted that German investors were reluctant to invest in stocks, but were generating hype about Bitcoin.

Bitcoin smashed through the US$8,000 level for the first time over the weekend and traded at US$8,216 at 10:23 a.m. ET on Wednesday, with many experts saying US$10,000 is possible.

An eightfold increase in the value of the volatile cryptocurrency this year has led to multiple warnings of a bubble, and institutional investors are broadly staying away.

Retail investors, however, as well as some hedge funds and family offices, are piling in despite JPMorgan Chase & Co (JPM.N) Chief Executive Officer Jamie Dimon earlier this year calling Bitcoin a "fraud".

Although UBS Chairman Axel Weber urged caution on Bitcoin last week, he also said there was potential for the technology underpinning it.

"At this point, I'm very cautious about Bitcoin as an entity. I'm much more optimistic about the underlying technology," Weber added.

Sweden's central bank is one organization which is investigating the potential for digital currencies.

"An e-krona would have the potential to counteract some of the problems that could arise on the payment market in the future when the use of cash is rapidly declining," the Riksbank said in a report in September.