Bitfinex controls Tether, a single source cryptocurrency supposedly backed by and pegged to the US dollar. The market cap of Tether has risen $188 million dollars to $678 million in one month:

https://coinmarketcap.com/currencies/tether/

If Tether is what they say it is, this can only come from investments of US dollars. Ie nearly $400 million dollars of investment in one month.

On November 21 Tether announced a hack in which they lost $30 million.

Bitfinex is extremely likely to be insolvent at this point. Users are complaining of an inability to withdraw funds on Reddit, and Bitfinex's Twitter has a days old announcement of a supposed DDoS attack, with no updates:

https://twitter.com/bitfinex

https://www.reddit.com/r/bitfinex/comments/7g8cp3/eth_withdr...

Tether has been traded on other exchanges for other cryptos, meaning that these other cryptos have been inflated by purchases with fake money.

This is a good outline of the scenario I think is about to play out:

https://prestonbyrne.com/2017/11/26/the-bear-case-for-crypto...

Bitfinex'ed is an anonymous Twitter and Medium account that is explaining the Tether fraud much better than I can:

https://twitter.com/Bitfinexed