We don't know their overheads.
actually we do https://mtgox.com/img/pdf/20120201/Transparency_Jan.pdf even if this is out of date.
Anyone who ready to put some work into it can figure out their revenue and expecens based on public information.
What not known is whether there is any revenue from a hypothetical side biz like "proprietary trading" and whether there are any large losses due to bank fraud, more hacks etc...
It was someone confusing because they quoted different things in different currencies, but the 5,000,000 yen they quoted for overhead worked out to about USD 62,000 per month. I expect that figure has increased with the increasing administrative burden imposed by AML/KYC compliance and we have no idea how much they lose to direct and indirect fraud, as Vladimir said. We also don't know whether funds which have been frozen in the past - Technocash, the French bank accounts, and even PayPal when Mark first took over MtGox - have now been released to them. We also don't know whether they still pay anything to the previous owners - remember that the MtGox hack happened when a third party had access to audit them because of this arrangement.
