plural is better if it is more frquently used in plural in an economic sense, for example: cars is better than car because if you build a website you don't want it to be about just one car, and stocks is better than stock because who wants to buy just one stock, it just doesnt sound right, so unless you are planning on a website that focuses on one particular high yield bond the plural is better, in some cases the singular is better, for example: fire vs. fires just ask yourself which one singular/or plural you would rather type in or build a website around..