yellow, white paint

I've used Dulux for over 40 years. My most recent, white gloss, paint jobs have all become yellow in a matter of months. If I wanted yellow paintwork, I would have bought yellow paint. Would this have happened if Dulux was still a British company owned by ICI ? I now use Wilco non drip white gloss. It`s much cheaper, gives an excellent, professional finish and it stays white. Michael