Bitcoin, the flagship cryptocurrency, has recently seen its price drop to $3,550 after trading at around $3,650 for a couple of days. This is notably the third time the cryptocurrency’s price drops suddenly this month.

According to CryptoCompare data, bitcoin is down about 3% in the last 24-hour period, as a little over $100 were slashed off its price in about 10 minutes, as volume surged. This was consistent with other sell-offs seen this month, which dragged BTC down from this month’s cuirrent high of about $4,050.

Bitcoin's price performance in the last 30 days

As a result, the cryptocurrency is down about 8.3% in the last two weeks, but is notably still up 10.5% in the last 30 days, as on December 15 it was at its $3,200 low, which some analysts believe may have been the bottom.

What’s behind today’s price drop is unclear, although data has recently suggested that BTC whales – holders with large amounts of the cryptocurrency – have recently started resurfacing. This, as whales who hadn’t touched their holding for between six and two and half years have started moving their funds as of last December.

Per data from Flipside Crypto, wallets active in the last days now hold roughly 60% of the flagship cryptocurrency’s supply. BTC whales can significantly affect the crypto market, as large buy and sell orders can easily see prices shift.

According to CryptoCompare, it would take a sell order of about 5,450 BTC ($18.8 million) for bitcoin’s price to drop 10% on the exchange. On platforms with lower liquidity, the amount is significantly smaller.

Bitcoin's orderbook on Bitfinex

As covered a study conducted y China’s state-run financial publication National Business Daily (NBD) found that about 0.7% of all bitcoin addresses control roughly 86.9% of the cryptocurrency’s circulating supply. This, as 97.2% of BTC wallets have less than 1 bitcoin in them.

As is often the case bitcoin’s slump dragged most altcoins along with it. At press time, Ether, EOS, Bitcoin Cash, and NEO are all down over 7% in the last 24-hour period, while Litecoin, XRP, and ZEC dropped between 3.9% and 4.6%.

TRON’s TRX is down by roughly 9%, while Ethereum Classic, a cryptocurrency that’s recently been hit with a 51% attack., has lost about 7.3% of its value.