Heading into month-end, Goldman's (skeleton crew) trading desk estimates that there is $21 billion of US equities to sell from US pensions given the moves in equities and bonds. The bank estimates the equivalent amount of bonds to be bought for month-end. The rebalance reached as high as $30bn before the modest selloff on Wednesday, and is now toggling in the $20bn range.
Putting this in context, $21bn to sell ranks in the 86th percentile amongst all buy and sell estimates in absolute dollar value over the past three years and in the 87th percentile going back to Jan 2000.
