I would suggest that part of Dash's price decline is due to people just honestly needing the money for other stuff. Even if you didn't invest more than you could (at the time) afford to lose, circumstances change over the years and sometimes it's necessary to partially cash out and hope you can buy back in later. I have done this and I know several others have as well. Fortunately I've been able to buy back in later, but if you're in a temporary cash crunch, sometimes selling your Dash is all you can do. Anyway, I think that's part of the reason.
Pretty much all alts are going down at the moment as the BTC rally continues. Look at LTC, NMC & PPC, well established cryptos that usually rise along with BTC; well currently they're not maintaining their natural peg or slight increase, they're all dropping too. It's just one of those periods where everyone gets the alt heebeejeebees and start bailing out. Dash is being affected in the same way. Just need to hang on until the sun starts shining again.
It's basically a bloodbath on poloniex, this morning all alts with a significant market cap (e.g. >1 million) suffered from a pretty hefty decline.
Might be liquidation on cryptsy etc to get out. Many speculators don`t have wallets for all the alts they hold, but Bitcoin is the safe haven.
That scenario would be reflected by dumps on craptsy, they can easily move their alts to polo without dumping.
