Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What is a financial security?
First, realize that Wikipedia is written by individuals, just like this board has thousands of members. The two definition were written and edited by different people, most likely.  Think Venn diagram.  The definition for financial instruments claims that it's the larger set, and securities is contained in a subset.  Comparing the two, it seems pretty consistent.  Yes, Securities include derivatives.  Transferable is close to tradable, although to me tradable implies a market as compared to private transfers.  I don't believe there's an opposite, per se, but there's 'other stuff.' My house has value, but is not a security. My coffee cup has no value. Back to the concept of Venn. There aren't really opposites, just items falling outside the set we're discussing.  I'd caution, this is a semantic exercise. If you know what you're buying, a stock, a bond, a gold bar, etc, whether it's a financial instrument or security doesn't matter to you.