cityboy

From the the pension balance sheet (liabilities and assets), calculate the total assets and then you can calculate the total asset Beta as:

Total Beta = Weight pension liabilities * Pension Beta + Weight operating liabilities * liabilities Beta + weight operating assets * Operating Beta

Typically As
Pension Beta = 0
Operating liabilities Beta = 0

You're left with
Total Beta = weight operating assets * Operating Beta

Use that total beta and plug it back in the equation below to isolate the "true" operating Beta

Total Beta = Weight operating assets * True Operating Beta + Weight pension assets * Pension Beta

That's about it...

J.