The final paragraph is the place to cover what else you would need to know before you are able to decide whether the conclusion is actually valid. This �what else� paragraph obviates the necessity for a formal conclusion. Useful statements are along the lines of:
In order to decide whether, indeed, ABC is actually the case, it would be useful to have access to XYZ.
XYZ might include one or other of: Expert opinion (. business consultant) / statistics / surveys / research data etc depending on the focus of the essay.
It is useful to end the essay on a note of doubt. Suggest that the argument might have a valid point, but that more information would be needed to come to a specific conclusion.