ComEd wants a $247 million rate hike on top of the $1.5 billion hike already pending – Crain’s*

The main driver of the increase is far higher interest rates, which caused the interest on Treasury bonds to rise in 2022. The old formula rate tied ComEd's return on equity — the profit it earns on its investments in the local power grid — to the yield on 30-year Treasury bonds. For most of those years that interest rate was low. That changed when the Federal Reserve hiked rates rapidly to combat inflation.