Hi all,
I am working with a panel data set (Orbis by Bureau van Dijk) containing information on millions of firms (mostly data from financial statements such as profits, fixed assets, turnover etc.).
Furthermore, the data contains information about the ultimate owner of each company, which allows me to group firms by their group ultimate owner (GUO). Each GOU owns potentially many different companies in different countries.
I am looking to generate a variable involving summations of variables within the GUO. Specifically, I want to generate the following variable, where B_{k,t} denotes estimated profit of firm k at time t.
Array

The tax variable is the corporate tax rate facing firm i at time t.

I have really been trying on my own, even generating the different parts individually. But the part regarding keeping tax rate i at time t constant while iterating over the tax rates in other countries at time t is causing me trouble. I am refering to the difference between the tax rates in the nominator.

Thank you in advance. This might not be an easy task - at least I don't think so.

Kind regards,
Jonas