• U.S.-traded spot bitcoin ETFs saw $1.2 billion in outflows between Aug. 27 and Sept. 6.
• This marked the longest streak of outflows since the launch of the funds, but it signals nothing but healthy growth, an expert said.

The recent plunge in the price of bitcoin (BTC) was accompanied by a sizable amount of net outflows from the 12 U.S. spot exchange-traded funds (ETFs). While on its face, that might appear worrisome, it's more likely a sign of healthy growth.

“This is going to be two steps forward, one step back," Eric Balchunas, senior ETF analyst at Bloomberg, said. "That’s the way many ETF categories are born and mature,” he added. “Nothing goes up in a straight line – flow-wise – ever because ETFs service long term investors and traders.”

The funds bled roughly $1.2 billion worth of bitcoin between Aug. 27 and Sept. 6, according to data from Farside Investors. At eight, that was the most consecutive days of net outflows that the ETFs have experienced since launching on Jan. 12.

The $1.2 billion represented roughly 3% of total assets in the funds, which, according to Bianco Research , stood at $46 billion after the outflows. Balchunas said a worrisome number would be more like 15%-20%.

The ETF issuers have mostly been blessed with sizable amounts of cash flowing into their newly-opened funds. In their first two months of trading, the ETFs saw net inflows totallng $12 billion, according to Bianco Research . Not as bullish on the funds as Balchunas, Bianco noted that the pace of inflows has since slowed, with just $4 billion of new money over the next six months, including only $1 billion over the past three months.

“The key to building a category isn't so much taking in money when there's good times, but it's limiting the outflows at bad times and I've seen these Bitcoin ETFs do a great job in the latter,” Balchunas said, referring to recent large price sell-offs associated with Mt. Gox and the German government, during which the ETFs quickly reverted to inflows after seeing only modest exits of money..

“The [ETFs have] really done a good job keeping bitcoin out of the abyss," said Balchunas. "They have saved bitcoin’s butt a couple times in the past couple months, from real, real depths."