The idea of acceleration is employed to ascertain the amount owed under foreclosure. Acceleration allows the mortgage holder the right when the mortgagor defaults on the mortgage to declare the entire debt due and payable. In other words, if a mortgage is taken out on property for $10,000 with monthly payments required, and the mortgagor fails to make the monthly payments, the mortgage holder can demand the mortgagor make good on the entire $10,000 of the mortgage. Virtually all mortgages today have acceleration clauses.
However, they are not imposed by statute, so if a mortgage does not have an acceleration clause, the mortgage holder has no choice but to either wait to foreclose until all of the payments come due or convinces a court to divide up parts of the property and sell them in order to pay the installment that is due. Alternatively, the court may order the property sold subject to the mortgage, with the proceeds from the sale going to the payments owed the mortgage holder. A mortgage holder bringing a foreclosure suit in court must join any "necessary" parties to the case.
To understand what a necessary party is, it must be realized that the purpose of a foreclosure sale is to sell the property as it was when the mortgage was first taken out. Anyone who acquired an interest in the property after the mortgage was taken out must be dealt with in the court case before the property can be sold. Necessary parties include parties who acquired easements, liens, or leases after the mortgage being foreclosed was executed. They can be added, or "joined" to the case as parties without their consent. The intent is to terminate their interest in the property.
If a party is not joined, then their interest in the property is not affected by the foreclosure, and the purchaser does not acquire an interest in the property fee of their rights. For instance, if party X takes out a mortgage from party Y and then takes out a second mortgage from party Z, and party Y decides to foreclose on the property and sell the property to party A at foreclosure, party Y must extinguish the interest of party Z to sell the property to party A. Otherwise party Z can enforce their mortgage on party A.
The other type of party involved in a foreclosure case is called a "proper" party. A proper party is a party that is useful, but not necessary, to a foreclosure case. An example would be a party who has an interest in the property before the mortgage was executed. Since this party would not be affected by the foreclosure, the individual is considered a voluntary party to a case and normally cannot be included in the case without consenting to it. However, often courts will require these parties to be joined anyway to the case to clarify their status with respect to the mortgage being foreclosed.
This is a situation wherein the foreclosure sale is not enough to satisfy the amount of the mortgage, the mortgage holder can bring a deficiency judgment against the mortgagor to make up the difference. For example, a mortgage holder of a $10,000 mortgage, who only receives $8,000 in a foreclosure sale, may sue the mortgagor for the remainder of the amount due under the mortgage. Deficiency judgments are tempered in many jurisdictions by "fair value" legislation. This requires the deficiency to be calculated using the difference between the mortgage debt and the fair value of the real estate.
In the above example, a court in a fair value jurisdiction might determine that the fair value of the property was $9,000. In that case, the mortgage holder could only obtain a deficiency judgment of $1,000. Currently, 29 states (Alabama, Alaska, Arizona, California, Colorado, the District of Columbia, Georgia, Hawaii, Idaho, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nevada, New Hampshire, North Carolina, Oregon, Rhode Island, South Dakota, Tennessee, Texas, Utah, Washington, West Virginia and Wyoming) allow foreclosure by the power of sale.
However, foreclosure by the power of sale is often subject to judicial review at a later date because there are issues about title that must be resolved by the court. These would include actual defects in the deed, and the priority of various lien holders and lessees on the property. In addition, in many jurisdictions the mortgage holder is prohibited from seeking a deficiency judgment if the holder chooses to sell the property through extra-judicial means. Also, the mortgage form must generally allow for power of sale and cannot be in the form of an absolute deed for a foreclosure by the power of sale to take place.