Hi Kimi,
There are a lot of governing hands in deciding the percentage of control, and doesnt depend on only the percentage of the share. I might buy 5% percent share in a company, but this doesnt mean that I have 5% influence on the decisions made by the management.
In lot of cases, when 2 companies get into engagements, they will have clear contract stating the share percentage, control percentages, etc.
Hope this helps.
