FOMC Watch | The S&P Fell After Five of the Last Seven First Hikes, Averaging 2.83% in Six Weeks

CME FedWatch shows a 92.7% probability of a 25 basis point increase at the September meeting, lifting the target range to 3.75%-4.00%.Axel Adler Jr. pointed to the historical record on first hikes. Among the seven since 1988, the S&P 500 declined six weeks later in five instances, with an average drop of 2.83%.Five of Seven Is a Tendency, Not a RuleThe sample deserves stating plainly before it gets used as a forecast.Seven episodes across 38 years is a small dataset, and five of seven means two produced gains. An average decline of 2.83% describes a modest move, not a rout — it is the kind of drawdown that occurs routinely without a policy trigger.What makes the pattern coherent is the mechanism rather than the count. A first hike marks a regime change, and markets that have been pricing one set of conditions take weeks to reprice for another.The market has largely priced this hike. The risk Adler identifies is what comes after: if the Fed signals a faster pace or that higher rates will persist longer, US stocks and Bitcoin could come under further pressure.Prediction Markets Sit Six Points Below CMEThe venue spread has been consistent all week and is worth tracking rather than averaging.predict.fun's market shows 88%. LSEG data put it at 93%, and CME has ranged from 92.5% to 94% depending on the snapshot. On Friday, Polymarket sat at 61% while CME showed 76% — a 15-point gap on the same binary event.Two explanations fit. Rates markets aggregate hedging demand alongside directional views, and a trader buying protection against a hike inflates the implied probability without believing in it. Prediction market participants take cleaner directional positions.The alternative is that prediction venues are thinner and slower to update, which on a fast-moving binary with a known resolution time argues for weighting the deeper market.At 88%, roughly one outcome in eight is still a hold.The Hold Is the Larger ShockThat residual matters more than its size.Chris Sullivan of Hyperion Decimus identified why: the bigger shock would come if the Fed does not hike, since that would leave investors wondering what policymakers see that markets do not.LMAX Group's Joel Kruger reached the same conclusion, seeing "greater potential for an outsized move in risk assets to the topside should the Fed ultimately fail to deliver on these hawkish expectations."Every major investment bank expects the move. UBS, HSBC, Barclays, Citigroup, Wells Fargo, Morgan Stanley, Goldman Sachs, Bank of America and JPMorgan have all converged, with Goldman and JPMorgan dropping hold positions to get there.The Path Is Where Forecasters Actually DisagreeThe September decision is the narrowest question on the table.UBS projects 50 basis points of tightening by year-end, Bank of America 75, and Deutsche Bank a sequence running September, December and March 2027. Markets price roughly 3.5 hikes over the longer term.Jefferies sits below all of them, with global economist Mohit Kumar arguing the first hike may be necessary from a credibility standpoint while subsequent moves depend on how long the war lasts and the trend of oil prices.Brookings senior fellow Robin Brooks framed the consequence for Chair Kevin Warsh: "There's no way he can live up to all the hikes priced, so the press conference will likely disappoint markets."That is precisely the scenario Adler flags in reverse. His downside case requires the Fed signalling faster or longer tightening; Brooks expects the opposite and sees the dollar falling and long yields rising as a result.Both cannot be right, and the dot plot decides it.Crypto Is Already Positioned DefensivelyBitcoin traded just above $76,000 after the Clarity Act failed its Senate cloture vote 49-50.Talos recorded a 28% net buying tilt toward stablecoins ahead of the meeting, against an 8% average selling tilt around previous FOMC meetings. Bitcoin buying conviction fell to 3% from 10% and ether to 9% from 23%.Spot Bitcoin ETFs shed $450 million Tuesday, the heaviest single-day outflow since June 25, with more than $570 million in leveraged futures liquidated — the most since August 22.Open interest ticked up to 688,000 BTC from 676,000 even as price fell, reading as traders adding bearish bets rather than closing longs.The Correlation Breakdown Complicates the Historical ComparisonAdler's framework assumes Bitcoin follows equities through the post-hike window. That relationship has weakened sharply.CoinMarketCap data show Bitcoin's short-window correlation with the S&P 500 falling to 0.43 from 0.75 in a single session, with the Nasdaq link at 0.30 from 0.60 and the Dollar Index at +0.08 against −0.54 over 30 days.Head of research Alice Liu attributed the breakdown to regulatory focus displacing macro drivers after the Clarity vote, warning that "the beta hedge that would have worked Monday is unreliable today, and today's FOMC reaction may be swamped by regulatory follow-through."At 0.43 and falling, a six-week S&P decline transmits to Bitcoin considerably less than the historical pattern would imply.Whether the accumulated stablecoins return to exchanges after the announcement is the signal worth watching. The decision comes at 2:00 p.m. ET with Warsh's press conference 30 minutes later.