levered returns and inflation

formula

\(r_\lambda\) = levered return

\(r_u\) = unlevered return

\(\lambda\) = leverage ratio

\(i\) = interest rate

\(\pi\) = inflation

\(r_\lambda = \lambda r_u - \frac{(\lambda - 1) i}{1 + \pi}\)

Some sanity checks:

set inflation = 0

\(r_\lambda = \lambda r_u - (\lambda - 1) i\)

or

\(r_\lambda = \lambda (r_u - i) + i\)

set leverage = 1

\(r_\lambda = r_u\)

some trials

ru π i λ rλ  
0.10 0.00 0.00 1 0.10 no leverage
0.10 0.05 0.00 1 0.10 5% inflation
0.10 0.00 0.07 1 0.10 7% interest
0.10 0.00 0.00 2 0.20 2x leverage
0.10 0.00 0.00 6.67 0.67 leverage reflecting 15% down
0.10 0.00 0.07 6.67 0.27 7% interest and leverage
0.10 0.07 0.07 6.67 0.30 inflation = interest
0.10 0.05 0.07 6.67 0.29 inflation < interest
0.10 0.07 0.05 6.67 0.40 inflation > interest
0.10 0.07 0.15 6.67 -0.13 inflation < high interest
0.10 0.15 0.07 6.67 0.32 high inflation > interest
0.10 0.15 0.15 6.67 -0.07 high inflation = high interest