'Past Performance Is No Guarantee...' - Goldman Warns 'Over-Concentrated' Stock Market Faces 'Real' Lost Decade

"Past performance is no guarantee of future results..."

That well known axiom holds some weight for sure, but as Goldman Sachs David Kostin and his research team point out, while only the gullible will extrapolate current returns forever, 'past performance' does actually infer future performance expectations... and that may mean disappointment ahead for many:

“Investors should be prepared for equity returns during the next decade that are toward the lower end of their typical performance distribution,” the team wrote in a note dated Oct. 18.