To answer OP's question: That would require those companies opening their books to you... which they won't. None of them are "public" companies, so we have no access to their financials.
Biggest miners? These are all more rumour based than otherwise, so you can't quote me.
Bitfury - 20MW data centre in the Republic of Georgia + other data centres, I can't really say how much more
KNC - 10MW data centre in Sweden
ASICminer - 10MW in China - They appear to have stopped adding capacity, but may have far more than 10MW
Bitmain - 10MW in China - Have stated they are not adding capacity due to electricity costs, but they may have far more than 10MW
Those are your "biggest" players
Minor players/former players
Spondoolies - their 5MW mine burned down in October
Chinese operations - there are numerous 1-5 MW operations in China - fewer than there used to be due to their power costs, but still several
Then you have 5 to 10 large mines in the United States and Canada who host for other parties (ASICspace, Great North Data, Mega Big Power, Bitcoin Asic Hosting, Segmining etc.)
And 3 to 5 large mines (at least one is run by Verne Global) in Iceland who host for other parties like Spondoolies cloud mining, Digital BTC etc.
What are their margins? Well, that's basically their electricity cost in these jurisdictions
Republic of Georgia - 3-4 cents/kwh
Sweden - 4.5 cents/kwh
China - 5-7 cents/kwh
US and Canada - 2.5 - 5 cents/kwh
Right now, with the best equipment, if you're price per kwh is above 10 cents, you're making less than 50% profit, before the cost of your machines, facility, electrical work, cooling, employees etc.
Which is to say, if your mine is in a 7 cents/kwh jurisdiction, you probably are not making any money. The electrical panels and transformers alone will be more than $500K per MW. (New and high quality equipment. See the Spondoolies mine for why you don't want to cheap out on your electrical work.) And then throw in the cost of mines.
Margins, even at a slightly recovered price, are tight.
That's more than information I can compute. Thank you for this.
I was just wondering maybe there was a way to know how much profit these companies make but as you mentioned it would be impossible since they won't give out such information.