https://www.merriam-webster.com/dictionary/speculative
https://www.dictionary.com/browse/speculative
https://www.dictionary.com/browse/speculation
I don't think they were intended to be random chance, but there's a lot of speculative risk involved in trying to determine whether individual stocks will increase or decrease in value & over what time period. That is true even if people have quite a bit of information available to them regarding the economy as a whole, and the individual stocks, and a lot of skill in interpreting those variables.