the action of forming an opinion, theory, or conclusion based on insufficient/incomplete evidence, or a theory/opinion thus formed, i.e. the action or instance of speculating something;
e.g. There has been speculation that they will be here tomorrow, but no one is sure of that.
(noun)
the action of investing in financial stocks, or other ventures such as property, with the risk of loss but the hope of profit;
e.g. The company has begun property speculation in order to grow their profits.