We see that BTC is down to 28% in last 7 days which is result of FUD made of from China banning BTC. But this is not the case, instead china is banning ICOs without proper licensing and refunded all ICOs done on chinese exchanges like LLT and TRX on Binance. China ordered exchanges to get proper license before operation in China and these exchanges are still operative for International users. So We cannot say that China banned BTC instead they banned BTC exchanges to operate without licensing.
Another reason was the FUD made because of Jamie a CEO of a bank and then propagation of this news as a important highlighted news as on CNBC, Express tribune and other international News papers and News channel did. This seems like Banking system backed this news propagated it to make people scare of BTC so they can invest in banking system. BTC is a Bubble is word most used to make people scared about their money invested.
All FUD resulted in crypto currency down from 150billion $ to 112 billion $ in less than a month. People are scared of their investment but big old trader are saying this that this will rise again so don't panic and sell their bitcoin at low price to make a loss instead hold and u will see a big increase in price very soon.
This FUD happened many times in throughout history of BTC from 2011 specially china is banning BTC so do not panic sell if u want to remain in cryptocurrency.
What are your opinion about main reason for this price drop?
I think bitcoin has been a bit overpriced the last 2 months, historically bitcoin gain stability in range between $2500-$2700 but in last 2 months the price went triple and its just normal if the price having sharp decline as the issues concerning china hit the btc market, some old proverb i keep in mind was "Be fearful when others are greedy and be greedy when others fearful", so when people start to panic when the bitcoin dropped sharply, thats the best way to start analyze when to start to be greedy