Collateral Damage - What is the Future of Collaterization in Securities Lending Programs?

What have been the collateral trends over the last 18 months?

• The borrower perspective - why equities over government bonds? Is cash still attractive?
• Can the "be more flexible - make more money" mantra be quantified from a revenue and risk perspective?
• Can haircuts be dynamically managed - if yes, what are the impacts?