Well, Torpig obtained credentials for 8310 accounts, so I'm guessing that's just a $10-1000 estimate of the loss per account. But from my experience, $1000 per compromised account seems quite a bit on the high side for credit card accounts (I have no idea about average loss for stolen brokerage accounts).
Edit: From the pdf
"A report by Symantec [37] indicated (loose) ranges of prices for common goods and, in particular, priced credit cards between $0.10-$25 and bank accounts from $10-$1,000. If these figures are accurate, in ten days of activity, the Torpig controllers may have profited anywhere between $83k and $8.3M."
As an aside, these amounts are a good reason you should you your credit card instead of your debit card.
Edit: From the pdf
"A report by Symantec [37] indicated (loose) ranges of prices for common goods and, in particular, priced credit cards between $0.10-$25 and bank accounts from $10-$1,000. If these figures are accurate, in ten days of activity, the Torpig controllers may have profited anywhere between $83k and $8.3M."
As an aside, these amounts are a good reason you should you your credit card instead of your debit card.