15 years ago my father gave about 15 000 Euro to a family member in exchange for her share in an inheritance (not materialized to this day). Now this family member has changed her mind and she wants to give my father 20 000 Euro, which is 15 000 Euro "adjusted for inflation". This amounts to 2% annual interest. I looked up the historical rates of inflation in my country and 20 000 is the correct amount. Needless to say, my father is not happy with this, since he could have used the money in a better way. The problem is that this agreement was verbal only and we do not have any documents to support any claim.

This has caused a great conflict in my family and I would like to find a way out of this by finding a retrospective interest rate that both sides would consider fair. The family member used the money to purchase an apartment where she lives until this day. The average interest level for mortgages in the last 15 years in my country is about 4%. However interest rate on 15 year government bonds issued 15 years ago is 5.3%. There simply is no "central" interest rate.

Another method of solving this would be to take the 20 000 Euro and to ask the family member to lend my father another 20 000 Euro for 15 years with a variable interest rate equal to the inflation rate. But this would not be completely fair to my father either, since any benefit, such as the 15 year essentially-interest-free loan that we are talking about, is more valuable in the past than it is today.

I would welcome any suggestions on how to find the fair value of 15 000 Euro of 15 years ago, expressed either as a sum of money or a service.

15 years ago my father gave about €15.000 to a family member in exchange for her share in an inheritance (not materialized to this day). Now this family member has changed her mind and she wants to give my father €20.000, which is €15.000 "adjusted for inflation". This amounts to 2% annual interest. I looked up the historical rates of inflation in my country and €20.000 is the correct amount. Needless to say, my father is not happy with this, since he could have used the money in a better way. The problem is that this agreement was verbal only and we do not have any documents to support any claim.

This has caused a great conflict in my family and I would like to find a way out of this by finding a retrospective interest rate that both sides would consider fair. The family member used the money to purchase an apartment where she lives until this day. The average interest level for mortgages in the last 15 years in my country is about 4%. However interest rate on 15 year government bonds issued 15 years ago is 5.3%. There simply is no "central" interest rate.

Another method of solving this would be to take the €20.000 and to ask the family member to lend my father another €20.000 for 15 years with a variable interest rate equal to the inflation rate. But this would not be completely fair to my father either, since any benefit, such as the 15 year essentially-interest-free loan that we are talking about, is more valuable in the past than it is today.

I would welcome any suggestions on how to find the fair value of €15.000 of 15 years ago, expressed either as a sum of money or a service.

15 years ago my father lent about 15 000 Euro to a family member in exchange for her share in an inheritance (not materialized to this day). Now this family member has changed her mind and she wants to give my father 20 000 Euro, which is 15 000 Euro "adjusted for inflation". This amounts to 2% annual interest. I looked up the historical rates of inflation in my country and 20 000 is the correct amount. Needless to say, my father is not happy with this, since he could have used the money in a better way. The problem is that this agreement was verbal only and we do not have any documents to support any claim.

This has caused a great conflict in my family and I would like to find a way out of this by finding a retrospective interest rate that both sides would consider fair. The family member used the money to purchase an apartment where she lives until this day. The average interest level for mortgages in the last 15 years in my country is about 4%. However interest rate on 15 year government bonds issued 15 years ago is 5.3%. There simply is no "central" interest rate.

Another method of solving this would be to take the 20 000 Euro and to ask the family member to lend my father another 20 000 Euro for 15 years with a variable interest rate equal to the inflation rate. But this would not be completely fair to my father either, since any benefit, such as the 15 year essentially-interest-free loan that we are talking about, is more valuable in the past than it is today.

I would welcome any suggestions on how to find the fair value of 15 000 Euro of 15 years ago, expressed either as a sum of money or a service.

15 years ago my father gave about 15 000 Euro to a family member in exchange for her share in an inheritance (not materialized to this day). Now this family member has changed her mind and she wants to give my father 20 000 Euro, which is 15 000 Euro "adjusted for inflation". This amounts to 2% annual interest. I looked up the historical rates of inflation in my country and 20 000 is the correct amount. Needless to say, my father is not happy with this, since he could have used the money in a better way. The problem is that this agreement was verbal only and we do not have any documents to support any claim.

This has caused a great conflict in my family and I would like to find a way out of this by finding a retrospective interest rate that both sides would consider fair. The family member used the money to purchase an apartment where she lives until this day. The average interest level for mortgages in the last 15 years in my country is about 4%. However interest rate on 15 year government bonds issued 15 years ago is 5.3%. There simply is no "central" interest rate.

Another method of solving this would be to take the 20 000 Euro and to ask the family member to lend my father another 20 000 Euro for 15 years with a variable interest rate equal to the inflation rate. But this would not be completely fair to my father either, since any benefit, such as the 15 year essentially-interest-free loan that we are talking about, is more valuable in the past than it is today.

I would welcome any suggestions on how to find the fair value of 15 000 Euro of 15 years ago, expressed either as a sum of money or a service.