Open market rent is the most common way of valuation at rent review it is also known as open market rental value  OMRV. It is most commonly defined as the rent at which the premises might reasonably be expected to let at, in the open market, at the review date, on the terms of the hypothetical lease. Typically, this is framed with a primary reference to the terms and covenants of the actual lease of the premises, however this is not always the case and due diligence is needed in understanding the particular definition of open market rent in any review clause.