Grantham said the US market has been acting as if it is oscillating normally enough, but around a much higher average P/E.

This is an attribution claim: did Grantham say, in a 2017 letter or interview, that the US market has been acting as if it oscillates normally around a much higher average P/E? TRUE if a primary source by Grantham from 2017 (a GMO quarterly letter, white paper or recorded interview) contains this statement or one essentially equivalent to it. MOSTLY TRUE if the statement appears in substance, but with small differences of wording or date (e.g. a letter dated late 2016 or early 2018), or without explicit reference to the US where context makes it clear. MOSTLY FALSE if Grantham discussed higher P/Es but framed it materially differently, e.g. said only that it was possible or explicitly rejected it. FALSE if primary sources show he said the opposite, or if the quote is shown to come from someone else.

Set before the research began.

1. E1 Viewpoints: I Do Indeed Believe the US Market Will Revert Toward Its Old Means – Just Very Slowly GMO (Jeremy Grantham) · 29 June 2017 Own record

   “My key question is: If we have a bear market soon, even a severe one, will it recover to the new normal of 23x or the old normal of 15x? I believe the former.”

2. E2 Viewpoints: I Do Indeed Believe the US Market Will Revert Toward Its Old Means – Just Very Slowly GMO (Jeremy Grantham) · 29 June 2017 Own record

   “Because of this stickiness, I have suggested that regression of P/Es and profit share will take 20 years”

3. E3 Viewpoints: I Do Indeed Believe the US Market Will Revert Toward Its Old Means – Just Very Slowly GMO (Jeremy Grantham) · 29 June 2017 Own record

   “I have suggested that although mean reversion in margins and price earnings ratios is still probable,”

The quoted sentence does not appear word for word in the evidence. Grantham's June 2017 GMO Viewpoints piece does make the same point in substance: he describes a 'new normal' P/E of 23x against an 'old normal' of 15x, and says he believes a bear market would recover to the higher level (E1). He also says mean reversion is still likely, but only very slowly, over about 20 years (E2, E3). That fits a description of how the market has behaved recently and does not reject it. Because the substance appears in a 2017 primary source but the exact wording is not confirmed, the verdict is mostly true rather than true.