The San Francisco Fed’s August Economic Letter says the stock-bond correlation “has flipped
for the first time in decades” — positive now, after decades in which Treasuries
could be counted on to rally when equities fell. Why a correlation flips with the shock mix, and why
2022 was the tell, is Stock-bond correlation flips with the shock type‘s territory; the letter’s contribution is
duration and confidence: three years of persistence, outside the bands.
The finding is not news to anyone who lived through 2022. The messenger is. Market claims
tend to age through three stages: first the people positioned in the trade say it, then the
financial press repeats it, and eventually someone official writes it down. “Bonds no longer
hedge” spent a couple of years in stage one as the respectable half of the
Debasement trade pitch — the half you could say without mentioning gold. A Fed research letter is stage
three. That does not make the full debasement thesis right; it moves its narrowest premise
from marketing material into the reference literature.
Portfolio math has to respond even where macro views do not. If the bond sleeve now moves
with equities, the insurance job is vacant, and the applicants are the familiar ones:
Hard assets, priced by the carry logic of Real rates and gold. The letter’s own
transmission story runs through oil — Oil is the inflation transmission is the channel that
keeps supply shocks feeding inflation while growth softens, and so the channel that keeps
the correlation pinned positive.
Two cautions, both from the KB’s own method notes. First, Check the stat against its own chart
applies to Fed letters too: “first time in decades” describes a correlation estimate with
wide bands, and the letter’s own figure dates the flip to 2022–23. What is new is only how
long it has now held — reading it as a fresh event overstates it. Second, the flip is how
The era of free money is over compounds quietly: duration now hurts twice, once through the
bond sleeve itself and once through the long-duration equities that used to trade like
bonds (Equity duration).
What is actually being repriced when the hedge dies is the compensation for holding
duration — the term premium. That is the note this analysis needed and the KB does not
have yet.
Missing notes
- term premium — the compensation for holding duration risk; the natural frame for what
a positive stock-bond correlation does to it.