I agree that 8% is unrealistic, but it's what many pension plans are using. [1]
The article I linked to (found via a quick Google) discusses using values of 6.25% to 6.75%. But IMO even that is unlikely, because one of the traditional investment pillars for pension funds is "fixed income" aka bonds, and those are way under that. Thirty yr US Treasury paper is just over 3%. A moderately risky company I follow (low investment grade) recently issued thirty year paper for 5.75%. [2]
The article I linked to (found via a quick Google) discusses using values of 6.25% to 6.75%. But IMO even that is unlikely, because one of the traditional investment pillars for pension funds is "fixed income" aka bonds, and those are way under that. Thirty yr US Treasury paper is just over 3%. A moderately risky company I follow (low investment grade) recently issued thirty year paper for 5.75%. [2]
[1] http://www.foxbusiness.com/economy-policy/2014/04/17/public-... [2] http://www.enscoplc.com/Newsroom/Press-Releases/Press-Releas...