Bitcoin drop 40% and others rallied, but it seems a bullish sign for cryptocurrency...

Is it a bullish sign... When Bitcoin plunged close to 40% back in the middle of December, Ripple took off, quadrupling in value in a matter of days to take second position among cryptocurrencies in terms of market capitalization. Meanwhile, other cryptocurrencies rallied in sympathy. Like Ethereum, Litecoin, NEM, Siacoin, and Bytecoin

"I wouldn't read too much into it," says cryptocurrency expert Kyle Samani. "The crypto market is 99% noise right now. In general, we see rotations between BTC and alts. First half of 2017 was alts, 2nd half was bitcoin, seems like we're back in an alt cycle."

There's a good explanation behind the rotation among Bitcoin, Ripple, Ethereum, and other cryptocurrencies. Some cryptocurrency exchanges require Bitcoins to pay for coin transactions. So, investors who already own Bitcoins have to sell them to execute those transactions.