Is Gemini, GDAX & Coinbase solvent!?

I often wonder if the major exchange systems that deal in crypto currency are financially solvent and how they will react with a major market correction. Financial transparency is almost unheard of in the crypto markets !

I worry that when a massive downturn does happen the exchange systems will go belly up.

Is the world not concerned of what will happen in a massive panic in the markets !? Are we being foolish with our money!?

It seems to me that the world is shooting from the hip in regards to this cyber security market place. I see tremendous risks.