In short prices are strong at the end of 2017 with increased demand.
304/1.4301 up EURO 100/tonne
316L/1.4404 up EURO 135/tonne
Just in case you are not Stainless Steel mad like we are here is an overview of AAF
The price of stainless steel is made of of two components, the base price and the Alloy Adjustment Factor (AAF).
The base price is based on the manufacturers cost for producing the material to a certain specification.
The AAF charge is for various alloys used (e.g. nickel, molybdenum) to produce the specific grade.
View the December 2017 update here