I understand English is not your first language, so I will break it down for you. The phrase "any other investment" means the object being discussed is also an investment.
"This vehicle is faster than any other car" means the vehicle in question is a car, not an airplane. By contrast, "This vehicle is faster than any car" means the vehicle in question is not a car.
I'm not sure English nuances are applicable in this very case. There is a concept in jurisprudence that defines how "other" should be treated (mainly in laws). Sorry forgot the latin term, in short, common sense (unsurprisingly, hehe) shouldn't be used.