Hi there.
My apologies for taking so long to get back to you.

There is about 8% wax in our pigment sticks.
There are no fillers, driers, stabilizers, or any other additives in our pigment sticks (with the exception of the blending stick w/ drier, which  contains cobalt drier).  Just oil, wax, and pigment.
 
Additives are often used to make the milling of large quantities of paint easier, and to generally make the characteristics of different colors (consistancy, drying time) somewhat homogenous.  They can also have a dulling and muddying effect on oil paints.
Our paints are milled in small batches to the specifications of each  pigment so that their individual characteristics show through.
This is why they are so brilliant even when mixed.

I hope that answers your question.
Lea

We can't lower the ratio of wax to oil and still have the sticks be sticks. 
It is the wax that allows our paints to hold their shape.
However, it isn't the wax that is making the paint dry slowly.
It is the pigment. 
For example, Cobalt Yellow - one of our fastest driers, will dry in 1 to 5 days, depending on how thick the paint layer is.  Indian Yellow - one of our slowest driers, can take between 45 days and 6 months to dry. 
These paints have the same basic ingredients.  It is the pigment that is different.
There are things you can do to help accelerate drying, such as using solvents or driers.  But mainly it is good to be aware of the drying rate of your paint before you apply it.  This information is available in our catalogs.

Lea