Have you ever tried to buy a company from the Companies for sale? No? Then try it yourself right now. If your answer is yes, then you must be familiar with my pain. I tried to buy a Q1 aircraft company to save 1 gold. This is what I came across:
The first compnay I was able to buy was on the 50th page!
If you didn't used this feature in the game recently, then this is the explanation:
After the holding update, you can only buy companies which are in the same region as your holding.
My suggestion is to implement a filter to the compnay market, where you can set the country and region, something like this: