3 accounts' buying activity drove an 8 percentage point increase in the probability of a Fed rate hike in December.

According to PolyBeats monitoring, from November 4 to 5, after the U.S. midterm elections confirmed that Democrats won both the Senate and the House, the interest rate market quickly repriced the December policy meeting.

On the prediction market Polymarket, the probability of "a 25 basis point rate hike after the Fed's December meeting" rose from about 70% on November 2 to 78%. During that period, the 3 accounts that bought the most "25 basis point hike" shares (excluding cross-market buying accounts) invested a total of about $147.4k, accounting for 51.6% of total purchases during that period.

Erasmus. bought $72.8k. This account's win rate across 44 market trades in the Fed interest rate sector is 81.8%, PnL −$495.2k, ROI −2.9%. This trade's investment was 0.19 times its average investment in this sector.
TheReturnOfDarthMaul bought $178.9k. This account's win rate across 40 market trades in the Fed interest rate sector is 80%, PnL +$1.4M, ROI +14.3%. This trade's investment was 0.7 times its average investment in this sector.
MJB bought $33.8k. This account's win rate across 1 market trade in the Fed interest rate sector is 100%, PnL +$1.6k, ROI +5.8%. This trade's investment was 1.2 times its average investment in this sector.

Why the midterm elections raised rather than lowered the probability of a rate hike comes down to roughly two lines of analysis. The first is political constraints: after Democrats control Congress, it becomes harder for the White House to unilaterally push a narrative of substantial easing or to reshuffle the policy committee on its own timetable. Mark Zandi, chief economist at Moody's Analytics, said the election results allow the Fed to operate in a way more consistent with its dual mandate, with reduced political constraints.

An Allianz economic research special report on November 4 also noted that Democratic control of the Senate will mainly slow personnel confirmations—including the pace of confirming Fed vacancies—thereby easing market concerns about erosion of Fed independence. The second is that macro risks have not disappeared: Allianz mentioned that fiscal gridlock, the debt ceiling, and spending frictions remain, and if Iran and oil prices escalate again, this could trigger a hawkish inflation shock; a Scotiabank Wealth commentary on November 4 emphasized that a divided government makes large-scale fiscal expansion harder to implement, and interest rates will ultimately still return to inflation, energy, and fiscal sustainability.