Puck value on player traded not the same as pucks received in sale

[leetchpic2]

I sold Steven Stamkos for 599,950 pucks but my account only increased by about 575,000 pucks.  What's the reasoning for not receiving the full amount of the trade?

[GingerBeardNinja]

When you put a player up for auction it tells you that EA takes a small portion as a fee or something. Surely you've put players up before and seen this bubble appear
Not sure what percentage the fee is but I think its just under 10% or something