Over the coming decade baby boomers will be retiring en masse. Many will be pulling money from their retirement accounts or receiving payments from their pension plans. This will mean selling assets and should be a headwind for valuations over the coming decade.
This will be a benefit to those who are currently saving money for retirement and investing for the longer term as it is better to be able to buy assets at lower prices. However, those who are investing for the shorter term and expect to return to the valuations of the past two decades might be in for a surprise.