OBLATORY ADVANCE
An advance made according to terms of a pre-existing construction loan agreement or mortgage.


OFFER TO PURCHASE
A written proposal to purchase real estate that becomes binding upon acceptance of the vendor.


OPEN OR CLOSED
The restriction or denial of repayment rights until the maturity of the mortgage is a "closed" mortgage. If specified on document as "open", then mortgagor can pay extra payments of principal sums at any time or at specified times, with or without repayment penalty.


OPEN END MORTGAGE
A mortgage under which the lender has the option of advancing more funds where, for example, the value of the property is anticipated to increase.


OPERATING EXPENSES
Generally speaking, all expenses, occurring periodically, which are necessary to produce net income before depreciation. Under some conditions these expenses are placed in two categories, namely, operating expenses and fixed charges.


OPTION
A right given by the owner of a property to another (for valuable consideration) to buy certain property within a limited time at an agreed price; an option holder who does not buy at or within the specified period loses the deposit and the agreement is cancelled.


OWNER
The lawful possessor of the title to real property.