Their fees are something like 10% if I remember correctly, and it has to count as "income" from a tax standpoint for anything that is more than the expenses that are being covered by the funding, thus the higher the amount raised, the higher the portion that needs to go to cover those "income taxes" is. So it could easily be a much higher percentage if the funding is overwhelmingly successful. At least that is the case here in the U.S., but with Guild Companion Publishing being based out of the U.K., I'm not sure how that will affect the tax status of those funds for them, or what can be included as an "expense" from a cost basis standpoint.
update/correction: their fees are 5% and then there is a 3-5% fee for payment processing via Amazon Payments, so it does work out to about 10% before taxes are figured in. Then income taxes, which will greatly depend on the country (and possibly state and local income taxes or similar locality taxes in other countries) could eat up anywhere from 15% to 40% here in the U.S. but not sure what they are in the U.K., but I would assume they are similar since they also have a very large and bureaucratic government (may be even worse there, I'm not sure).
