Are there any financial instruments that offer a set real interest rate rather than a set interest rate? For example, an asset structured like this:
The asset is purchased at an initial price $P$ and matures after time $T$ (in years) to a value of $M$.
$M$ is defined as $P\times(1+inf)^T\times(1+r)^T$ where $inf$ is the average inflation rate between the time of purchase and maturity and $r$ is an agreed upon rate.
I am interested in this type of investment because it appears to guarantee the investor a very predictable increase in value that is independent of inflation.