G. Kärger was a lathe manufacturer. It's interesting to see them spending so much on a capital outlay, I wonder if they were expanding production? It could have just been replacement parts or a maintenance contract or something if those were offered back then, but it seems a bit much to be writing checks for 2x the amount as you're giving Krupp if that's the case.
Otto Mansfeld is an odd one, and most interesting as it's the single biggest line item by far. I'm mostly turning up a mining company by the same name, but not located anywhere near Stuttgart. I'm also a bit at a loss what Mauser would be directly buying from a mine (as opposed to a refining company) except for maybe coal and I can't imagine they were going through enough coal for it to be their #1 expense. That's where I'd start my digging on this particular list.
The cast steel on line 2 is pretty self explanatory.
Hahn + Kolb is a tool company and still around. My earlier comments about Kärger also apply here. Having your #3 expenditure be tooling is pretty significant.
AEG electrical and unless I'm mistaken AEG Berlin is turbines. Which would make sense if they were doing a big expansion that year and needed to up their on-site generation capabilities.
Nabenfabrik Alfing is a metalworking company that's still around under a slightly different name. Some light poking around suggests they mostly did big metal forms, the kind of thing you'd use in building construction etc.
Bizerba is an odd one, they make industrial scales.
Looks like after that we're into raw materials. The next two are wood companies which tracks as the stock was the most expensive component, and then a stainless steel company.
Andreas Daub is another interesting one. They were (and are) a jewlery company. Maybe my earlier comment re: Thales was wrong and there was a fair bit more converting of small manufacturing than I'd thought, or maybe they were providing something directly that Mauser could use. This is one that someome should do some more digging on, I'm pretty sure the answer will be interesting. edit: Ok, I have another source (Deutsche Fertigungskennzeichen bis 1945) that lists them as a jewlery and chain company so that might make some sense. Still that's a big expendature on chains (and presumably fine ones at that if it's coming from a company that also makes jewlery) if that' what it is. I'd also put in a hedge bet that it could be watches or clocks, as that was frequently intermixed with jewlery back then. Their manufacturer code was jqb if anyone has ever seen a part coded that way.
I'm going to stop there for now.