Options expiring tomorrow are a big factor of this dip, not just the tax news.

First let me educate on how options work. An option is a contract for to buy or sell 100 units of a stock/coin set at a certain price if the price is above (call) or below (put). These contracts are sold at a premium per unit.

For example Nano is 7.16 right now and lets say I own 100 coins but to protect myself in the event of it mega crashing to 0 I can buy a $6 Put. The premium to buy this might be $0.50 PER UNIT, so in this case $50 total. The person I bought the contract from for $50 is agreeing to buy all 100 of my NANO for $6 each even if it dropped to $0 by the time the contract expires. So if it doesnt drop below $6 that $50 I just paid him becomes worthless on expiration and that person just made a free $50. This person profits as long as the coin doesnt reach a price of 5.50 ($6-0.50 premium)

This is where the game gets played, options are expiring today. As of last week we were sitting pretty around $60k so the lower price option premiums were probably absolutely dirt cheap as there is "no way BTC drops by $10k in a week before expiration" so the sellers of these contracts are just trying to get free money. However Whales will buy a shitload of contracts that are basically worthless due to theta decay since the expiration is so close, then they can create a huge sell off at these high prices, tank the price, then they can either excercise these options or sell them for massive gains as they had just bought them for dirt cheap just last week. Then after expiration they can just reload their bag and then some with these extra profits at a lower price. So not only do they sell high, they profit on these dirt cheap puts they buy and are able to gain a much larger position by buying more coin or flipping it over and buying calls as the price will increase throughout the next month. This process just keeps spinning like a wheel.

This has happened at the end of the last 3 months like clockwork.