Eerie similarities to 2013
A year after the block reward halving, with media buzzing about Bitcoin, and a multifold increase in price - this is not just a description of 2017 but also perfectly fits 2013. After the block reward halving in 2012, the price of Bitcoin shot up during the following year. The price increased from around $13 at the starting of 2013 to a peak of over $1200.
The reasons for this jump are manifold (including the bots - Willie and Markus, which bought Bitcoins on Mt. Gox), but the almost 100 fold increase in price was unprecedented. The 500% increase in price of Bitcoin in 2017 appears tame in comparison. Of course, the base effect does make such 100 fold increases in price almost impossible now, with Bitcoin's market capitalization crossing $100 Bn.
This time Is different
When comparisons to 2013 are made, the common refrain is “this time is different.” There is increased Bitcoin adoption, there is no Mt. Gox, the ecosystem is better developed, institutional money is coming in and so on. If time has taught us one thing, it is that history usually repeats itself. Or rather, as Mark Twain said, “History doesn’t repeat itself, but it often rhymes.”
A 500% increase in price in just a year is the sign of a bubble building up. There has been no catalyst driving the growth and a fear-of-missing-out mentality seems to be at play. Newbies are being attracted to Bitcoin (and ICOs) driven by the promise of massive gains. They believe that "this time is different."
House money at play
While traditional economists believe that the market is made up of rational investors, behavioural economists believe otherwise. People who have made windfall profits take higher risks than they normally would. This is similar to gamblers taking higher risks after winning, believing that they are playing with "house money."
With Bitcoin's rapid rise in price this year, a lot of investors have seen their portfolio appreciate rapidly in price. Rather than evaluating whether Bitcoin is overvalued and it is time to sell, these investors may be willing to hold longer because of their windfall profits.
2013 ended badly
The crash of 2013 was the first long term downtrend in Bitcoin's price. Although there were previous crashes with higher percentage drops (from $32 to $2), this was the first time that the price didn't recover quickly. Bitcoin's price had risen during every calendar year until 2013 and people believed the price would recover in 2014.
This was not to be. It would take more than three years for the price to cross the $1200 levels attained in November 2013. This year has been extremely strong so far, but a crash would be terribly painful. A lot of recent cryptocurrency converts could get hurt and it could take even longer to recover this time.