Brands - who owns what?!

Brands always interest me as I always see them as separate to each other, but in reality many companies own different brands. The ones that intrigue me are the brands that I think are completely unconnected.

Below is a list of companies and some of the brands they own:

- Mondelez: Oreo, Cadbury, Milka, Philadelphia, Dairylea, Ritz

- Unilever: Comfort, Dove, Flora, Hellmann's, Lynx, Magnum, Ben and Jerry's

- Mars: Pet food, Dolmio, Uncle Ben's, Starburst, Wrigley's Chewing Gum, Mars Bars, Snickers

- Nestle: Kitkat, Maggi, Pet food, Nescafe, Breakfast cereals, cereal bars

- Proctor and Gamble: Fairy, Head and Shoulders, Herbal Essences, Oral-B

I find it interesting that many consumers are unaware some of these brands are even connected, especially when you may consider them to be "competitors" of each other, for example I always thought Head and Shoulders and Herbal essences were competitors so change my shampoo occasionally to try out a new brand and it turns out they are technically the same company!

I also had no idea that Mars who produce Mars Bars, Snickers,Twix etc. also offer pet food and sell Uncle Ben's rice. In my opinion, these products aren't connected and this leads me to ask; Does it hinder a company if they have items in different product categories?

Surely, you can't be a strong market leader in all categories when you have a variety of different products ranging from chocolate to detergent? However it clearly is worth doing as many of the above companies have a wide portfolio range. I love anything like this that makes me wonder how things work as I am so curious about random things!