There's a big hashwar playing out on the Bitcoin Cash blockchain. I'm guessing that's what the drop in price is about. Basically the gist of it is that one side, the Bitcoin ABC devs, want to optimize the software and upgrade gradually. Currently, blocks can't really function properly beyond a 22MB size, and they want to improve the software to scale for the current 32MB limit (approaching VISA scale transaction throughput; currently blocks are only being filled to 2/3MB, so much of this is purely theoretical longterm thinking).
The other side,
Bitcoin Cash SV (Satoshi's Vision), wants to increase the blocksize to 128MB and ultimately remove the cap entirely. I'm not sure what their dev roadmap is exactly to have functioning blocks at that size, but they seem to be more inline with the miners' longterm thinking. The thing about Bitcoin is that there's a give and take between three sometimes competing interests- the miners (who choose which chain is valid), the devs (who write software), and the users (who make the economic decision for which chain to support). I'm not sure if Craig Wright is just merely a psychopath or also a visionary, but him, nChain, and Calvin Ayre (billionaire with tons of mining hashpower) are kind of at the forefront of this thing.
The fork happened yesterday. However, this fork does not have replay protection. If you hold BCH, it's not as simple as getting free coins like the original BTC/BCH fork. Much of it depends on where your coins were being held- some exchanges/wallets will support both, some are basically waiting for a winner to emerge before building out their platform. Me personally, I just left my coins on my Ledger wallet and am waiting for this thing to blow over. The lead Ledger dev, Chip, has said they're going to keep an eye on it for a couple months and make a decision once things flesh out a little bit. I burned myself pretty hard trying to make moves before the BTC/BCH fork, I'd just as soon not fool with it anymore and let the chips fall where they may.
Going into it I felt that Craig's threats of litigation, chain death, and emotional outbursts are way beyond the pale and not inline at all with Bitcoin, which was founded originally as a way to free people from the financial system. I still feel that way. But I think he's forcing an interesting hand that I've not really seen play out before. BTC/BCH's fundamental disagreement was between developers and users, what kind of roadmap users wanted for bitcoin and Blockstream's failure to scale bitcoin to a modern, functional state. But this is an outright war of processing power, basically a system being decided by miners. This is billions and billions of dollars in mining infrastructure.
For its part, much of the ecosystem has sided with ABC and view the BSV camp as a hostile attack on BCH. Wright, by being a tyrannical #######, may have singularly driven away too much of the would-be support for SV to win a fight it might have won. But it's interesting to watch none the less. I wouldn't write off SV. They clearly have an intriguing vision for what bitcoin ought to be. I consider it favorable to BCH that this is playing out on its ecosystem.
Here's some background:
Bitcoin Stuff - I think I figured out nChain's business model
nChain's Jimmy Nguyen on Bitcoin SV
The Economics of Bitcoin (Part 1)
And of course:
Craig Wright during the BCH Hard Fork [LIVE]