The financial fate of homeowners with mortgages totalling almost R190 billion hangs in the balance as South Africa's most senior judges ponder whether or not banks can legally adjust your home loan rate.
The controversial case, aired before a full bench of the Appeal Court, led by Chief Justice Ismail Mahomed, has implications for all loan agreements, including overdrafts, hire purchase agreements and credit card debt.
Judgment has not yet been given.
At the heart of the issue is a clause contained in bond documents which gives your bank the power to adjust your interest rate up or down and with it, your monthly bond repayments.
Lawyers for the borrowers argue that this clause gives banks an unfettered, unilateral right to make changes to your home loan contract and that this is wrong because a contract must be an agreement between two parties as to their respective obligations.
The case heard in the Appeal Court relates to three judgments on bond rates in Durban, Johannesburg and Cape Town over the past year.
The three banks involved are Absa, Standard and NBS/Boland.
Others cases have been heard in courts around the country, with the banks winning some and the borrowers winning others, but this is the first time that the issue has been taken to South Africa's highest court.
The outcome of the combined case may have drastic consequences for borrowers.
The banks argue that they have the right to amend your interest rate from time to time because your rate is based on what it costs the banks to make the loan available to you.
They also say that the competitiveness of the rate is ensured by the open market.
If the court finds for the banks, banks would be entitled to adjust your interest rate up or down in line with fluctuations in the cost of money.
Borrowers who failed to pay their instalments while waiting for the outcome of the court case may be called on to make good their debt.
However, if the court finds that the banks have been acting illegally, the consequences for borrowers could be just as profound.
This is because your loan might have to be recalculated at the rate at which you signed your home loan contract and the rate could be fixed for the duration of your bond.
Whether you will be better or worse off will depend on the interest rate that you signed up on with your current home loan.
* If you signed up at a rate lower than the rate you are paying now, you could score.
* If you signed up at a rate higher than the rate you are paying now, you could lose out.
The judges did not give any indication when judgment will be handed down, so the bottom line is that borrowers will have to wait and see.