Some of the retail euphoria which helped push US equities into bull market territory may be waning.

Although re-leveraging from previously under-positioned professional investors likely played a key role in allowing stocks to build on gains driven in the first instance by an ongoing bid from systematic cohorts (which dialed up exposure as realized volatility collapsed), there was evidence aplenty of retail froth.

One such indicator of individual investor interest receded materially this month, according to JPMorgan’s Nikolaos Panigirtzoglou, who looks at small traders’ call option flow to gauge the retail impulse.

“This flow had increased markedly… point[ing] to a re-emergence during May of younger cohorts of investors who tend to use leverage via margin accounts, and tend to invest in the equity market via individual stocks or options on individual stocks, but June has seen a significant reversal of this flow,” Panigirtzoglou wrote, in a Thursday note.

Indeed, half of the crescendo witnessed in and around Nvidia’s “guide heard ’round the world” has retraced (red arrow in the figure above).

Obviously, you can’t read too much into any single indicator, but it certainly does feel as though some of the joie de vivre which defined the melt-up has gone missing, even if it’d be a mistake to say the thrill is completely gone.

The latest read on the AAII bull index was 41.9%, the lowest since May 31. This week marked the second consecutive weekly decline.

The sudden inflection witnessed at the tail end of May (and it extended into mid-June) was indicative of contagious FOMO. Individual investors probably still have the fever, so to speak, but it’s not as intense as it was.

“[Other] proxies of the US retail impulse into tech-related individual stocks are sending a similar message to the reversal of May’s buying impulse from younger cohorts in June, though more modest than that implied by option flows,” Panigirtzoglou went on.

“Equity baskets containing stocks popular with US retail trading platforms” are saying broadly the same thing, he added.