It is a bit work to figure out the ownership structure of companies in Norway. The information is publicly available, but one need to recursively look up ownership for all owners to figure out the complete ownership graph of a given set of companies. To save me the work in the future, I wrote a script to do this automatically, outputting the ownership structure using the Graphviz/dotty format. The data source is web scraping from Proff, because I failed to find a useful source directly from the official keepers of the ownership data, Brønnøysundsregistrene.
To get an ownership graph for a set of companies, fetch the code from git and run it using the organisation number. I'm using the Norwegian newspaper Dagbladet as an example here, as its ownership structure is very simple:
% time ./bin/eierskap-dotty 958033540 > dagbladet.dot real 0m2.841s user 0m0.184s sys 0m0.036s %
The script accept several organisation numbers on the command line, allowing a cluster of companies to be graphed in the same image. The resulting dot file for the example above look like this. The edges are labeled with the ownership percentage, and the nodes uses the organisation number as their name and the name as the label:
digraph ownership {
rankdir = LR;
"Aller Holding A/s" -> "910119877" [label="100%"]
"910119877" -> "998689015" [label="100%"]
"998689015" -> "958033540" [label="99%"]
"974530600" -> "958033540" [label="1%"]
"958033540" [label="AS DAGBLADET"]
"998689015" [label="Berner Media Holding AS"]
"974530600" [label="Dagbladets Stiftelse"]
"910119877" [label="Aller Media AS"]
}
To view the ownership graph, run "dotty dagbladet.dot" or convert it to a PNG using "dot -T png dagbladet.dot > dagbladet.png". The result can be seen below:
Note that I suspect the "Aller Holding A/S" entry to be incorrect data in the official ownership register, as that name is not registered in the official company register for Norway. The ownership register is sensitive to typos and there seem to be no strict checking of the ownership links.
Let me know if you improve the script or find better data sources. The code is licensed according to GPL 2 or newer.
Update 2015-06-15: Since the initial post I've been told that "Aller Holding A/S" is a Danish company, which explain why it did not have a Norwegian organisation number. I've also been told that there is a web services API available from Brønnøysundsregistrene, for those willing to accept the terms or pay the price.