Why would that happen? The halving means that there will be only 1800 BTC per day to be mined rather than 3600. Many miners will have to stop mining, starting with those with smaller efficiency (hashes per dollar of electricty and other recurrent costs). It is not clear whether these miners will be small or large. My guess is that mining will become more centralized, and more China-based.
The price of bitcoin has halved 2-3 times since the ATH. In terms of mining profitability, effect of price halving and reward halving are just the same, since miners are paying bills in fiat. Therefore, a planned reward halving should not have a very dramatic effect on the hashing power (see what happened after the first halving in 2012).
That is one reason why one cannot take the past halvings as precedent for what will happen in the next halving. Since it takes months to set up a large mining farm, mining is very profitable while the price is rising fast. If, at the previous halvings, miners were making more than 100% net revenue over their recurring costs, the halving of the reward still left them profitable. No wonder that there was no significant drop in the hashrate in 2011
Now, we have many miners who ordered their equipment in late 2013, counting on four-digit prices, only to see the price drop by 80% over the last 15 months. So, today the miners must not be making that kind of profits anymore. We don't know for sure, but most comments that I have seen say that, or worse. If the price does not double before the next halving, many miners will surely shut down.
Also, price is expected to raise after halving due to decreased supply, which will compensate at least part of the loss of reward halving.
The last halving was on 2012-11-28. The price did not register any change, and remained flat for nearly a month at ~12 $/BTC, until the next bubble started (on 2013-01-06) that took the price to a peak of 226 USD/BTC. In fact, the price was rising until 2012-11-28, and stopped rising then.) There is no evidence that the early 2013 bubble was due to the halving; on the contrary, there are several hints that t was actually due to adoption in China through BTC-China.
Since conditions are so different, the next halving
may cause an price increase; but it may also have been "priced in", as they say, and have no effect at all.
Thanks, I will check.
