As of October 15, Costa Rica's Rebeca Grynspan is still the most likely next UN Secretary-General, but we cut her to 40 percent from 46. Politico reported the U.S. opposes all seven declared candidates and wants new ones, and PassBlue's sources say one of her six discourage votes on October 7 was American, a day before the first veto-revealing ballot.
Why it matters: The next Secretary-General will run the UN through a period of deep U.S. funding cuts and reform demands, shaping how the organization handles wars, humanitarian aid, nuclear inspections and trade disputes that touch American interests.
May be out of date. This forecast's evidence stops on October 15, 2026, 25 days ago. The desk reviews stale forecasts first; a new version will appear here when the evidence moves.
TPG forecast: most likely
Rebeca Grynspan
40%
Grynspan leads, but Washington is the obstacle
Rebeca Grynspan40%
Someone else26%
Rafael Grossi13%
Carolyn Rodrigues Birkett9%
Maria Fernanda Espinosa4%
Kalshi prices Rebeca Grynspan at 54% on Oct 15, 2026
Our odds over timeTPG forecastMarket
Version 3: 40% (range 28% to 52%) · Kalshi 54%
Evidence cutoff Oct 15, 2026 · published Oct 15, 2026 · Grynspan leads, but Washington is the obstacle
The field
Every contender, the odds, and the record on paper. Record facts are sourced; we forecast who is most likely to win, not who should.
01Rebeca Grynspan
Secretary-General of UNCTAD, former Vice President of Costa Rica
Vice President of Costa Rica 1994 to 1998; head of Ibero-American General Secretariat 2014 to 2021[13]
The caseShe has led four of five straw polls, is the only candidate reported at the nine-vote threshold, and China and Russia are not reported among her opponents.
The riskSources say the U.S. cast one of her discourage votes and the administration wants new candidates; one red ballot on October 16 would end her bid.
02Someone else
Any candidate not listed, including a late entrant such as Feridun Sinirlioglu or Nickolay Mladenov
26%
The caseThe U.S. has said it wants new candidates, Turkiye is reported to be considering a nomination, and deadlocks produced compromise winners in 1981 and 1996.
The riskA late entrant has only weeks to campaign before Guterres's term ends on December 31, and Council members are wary of starting over.
03Rafael Grossi
Director General of the International Atomic Energy Agency
13 years in high office
13%
Fifth straw poll, Oct. 7
6 encourage, 7 discourage, 2 no opinion, second place[26]
Permanent-member opposition
Russia has openly said it does not support him[22]
Prior offices
IAEA Director General since 2019; Argentine Ambassador to Austria 2013 to 2019[14]
The caseHe finished second on October 7 and is reported to be Washington's preferred candidate.
The riskRussia has said it does not support him and Britain is likely to oppose him over the Falklands, so he faces two possible vetoes.
04Carolyn Rodrigues Birkett
Guyana's Ambassador to the UN, former Foreign Minister of Guyana
The caseAs a declared Latin American candidate she fits the regional rotation and could gain if the leaders are vetoed.
The riskShe has not been reported near the top of any straw poll.
The numbers behind the call
9
encourage votes for Grynspan in the October 7 straw poll, the minimum needed, and first place[19]
6
discourage votes against her that day, cast by the U.S. and five elected members according to PassBlue's sources[20]
October 16
date of the first colour-coded straw poll, where permanent-member vetoes become visible[21]
11
encourage votes: the floor Antonio Guterres never fell below in 2016[8]
16 rounds
of deadlocked voting in 1981, the last time Latin America won the job[10]
What it means for you
U.S. taxpayers and Congress
Washington has cut UN funding and says it wants a reform-focused manager. A Secretary-General the Trump administration backs, such as a candidate it does not veto, is more likely to deliver budget and staffing cuts that Congress then weighs against future U.S. contributions.
Americans following Middle East and Ukraine diplomacy
The Secretary-General sets the tone for UN mediation and humanitarian operations. A Grynspan or Rodrigues Birkett term would likely emphasize development and multilateral trade; a Grossi term would bring a nuclear-inspection specialist to the top job at a time of Iran tensions.
U.S. exporters and businesses
Grynspan has led the UN's trade and development body since 2021, so her selection would put a trade economist in charge as tariff disputes reshape global commerce. Other candidates would put less emphasis on trade policy.
Latin American diaspora communities in the U.S.
Most of the leading candidates come from Latin America and the Caribbean. The region has held the post only once, from 1982 to 1991, so a win would be a significant symbolic moment for the hemisphere.
The deciders are the five veto holders, and the United States has now said in private what it wants: a reformer and, in a State Department official's words, a little bit of a disruptor. Politico reported on October 10 that the administration opposes all of the current contenders and wants new ones. That is a costly position only if it is enforced with a red ballot; until then it is leverage, and PassBlue's sources say Washington is not yet ready to shut the door on Grynspan. Our read is that the U.S. is bargaining for commitments on reform and senior posts, but it has shown it is willing to block.
Grynspan's strategy remains the low-audience-cost one: an economist running a technical UN agency, with no public fights with any permanent member, and a new conservative-leaning government at home that has cultivated ties with Washington. The other veto holders are now less of a worry for her than in version 2. PassBlue reports that Russia has openly said it does not support Rafael Grossi and that Britain is likely to oppose him over the Falklands, while China says it will not back a candidate seen as doing another permanent member's bidding. That leaves the U.S. as the decisive vote on her.
02
History
What happened the last times this came up?
Reference class: contested Secretary-General selections since 1981. The early leader in Council voting won in 1991 (Boutros-Ghali, who co-led the straw poll), 2006 (Ban Ki-moon led every poll) and 2016 (Guterres led every round). The early leader lost in 1981, when the United States blocked Salim Ahmed Salim through 16 rounds, and in 1996, when Boutros-Ghali had 14 of 15 votes and was vetoed by Washington alone. That is 3 of 5.
The closest analogue is 1981, the only previous time Latin America won the job. The Council deadlocked, the leaders were vetoed, and a dark horse, Javier Perez de Cuellar, emerged as the compromise. It breaks in one important way: in 1981 the frontrunners were blocked by votes everyone could see, while in 2026 the only signals so far are anonymous straw-poll votes and press reports of U.S. objections, ahead of the first colour-coded ballot on October 16. The 2016 comparison still cuts against her: Guterres never fell below 11 encourage votes, while Grynspan has hovered at or just above the nine-vote line in every round.
03
Statistics
Base rate, adjustments, the number.
Start from the base rate: the early straw-poll leader has won 3 of the last 5 contested selections, about 0.60. Version 2 cut that to 0.46 for Grynspan's thin lead and the risk that a veto holder was among her discourage votes. We correct one point in that version. It said two of her discourages might have come from China and Russia and that no permanent member had publicly opposed a candidate. Politico's report of October 10 (we read it in Yahoo News' syndicated copy), two days before that version's cutoff, said the U.S. opposed the whole field, and PassBlue reported on October 14, citing several sources, that her six discourages on October 7 came from the U.S. and five elected members. Version 2 missed the Politico report. Both rest on anonymous sources, so we weight them as strong reporting, not as confirmed votes.
Adjustments, our calculation: minus 8 points because the one veto holder reported to be voting against her is the one that vetoed the early leader in both 1981 and 1996, and it has said it wants new candidates; plus 2 points because China and Russia are no longer reported among her opponents and PassBlue's sources say the U.S. has not closed the door. 0.46 minus 0.08 plus 0.02 is 0.40. Grossi moves to second at 0.13: he finished second on October 7 with 6 encourage, 7 discourage and 2 no opinion, PassBlue reports he is Washington's preferred candidate, and Kalshi prices him second, but Russia has said it does not support him and Britain is likely to oppose him, so two vetoes hang over him. Rodrigues Birkett falls to 0.09 after 5 encourage and 9 discourage on October 7 and reports that her Gaza statements cost her U.S. support, which her campaign disputes. Ivonne A-Baki, a declared candidate, gets 0.02. Someone else rises from 0.14 to 0.26: a U.S. demand for new names, Turkiye's reported interest in nominating Feridun Sinirlioglu and the 1981 and 1996 precedents all point to a real chance that the winner is not on today's list.
Between the lines
What people spent versus what they said, and what was left out.
Personnel move
A State Department official told Politico that Nickolay Mladenov, head of the Trump-created Board of Peace, could not be ruled out, and Infantino was named as a good option, though neither is a declared candidate.
Washington is naming people who owe their current standing to it. That is the clearest sign yet that the U.S. wants a candidate it helped make, which is bad news for a field built before the administration engaged.
What was left out
PassBlue reports that Britain tried to delay the colour-coded ballots, which its diplomatic sources read as an attempt to hide opposition to Grossi.
Veto holders prefer to block quietly. Anonymous white-ballot rounds let them shape the field without being blamed; the colour-coded round on October 16 removes that cover, which is why it is the most important event left in this race.
Sequencing
Politico's report that the U.S. opposes all seven candidates came three days after the October 7 straw poll in which Grynspan's discourage votes doubled to six.
The order suggests the U.S. used the anonymous ballot first and the press second. It is building a public case for new candidates before any red ballot is cast, which gives it the option to veto later at lower cost.
Cheap talk
The State Department said the U.S. will only support a nominee with an unwavering commitment to drive meaningful reform.
This is cheap talk that any candidate can echo. What matters is whether Grynspan can make concrete commitments on staffing and budget cuts that the administration counts as reform before the colour-coded round.
History vs the market vs our call
Our number after adjusting the base rate for what is different this time: 40%. It sits inside the historical interval.
Check our statistics yourself
Reference class
3 of 5 (60%)
Exact 95% CI (Clopper-Pearson)
14.7 to 94.7%
Bayesian 95% credible (uniform prior)
22.3 to 88.2%
Binomial test of our 40%
p = 0.395
Our 40% sits inside the historical interval: the forecast is consistent with how cases like this have gone.
Reproduce in JASP (free, jasp-stats.org)
Download base-rate.csv (one row per case in the reference class, outcome 1 or 0) and open it in JASP.
Frequencies, then Binomial Test. Variable: outcome. Test value: 0.40. Tick Confidence interval. JASP reports the same p value and Clopper-Pearson interval shown here.
Frequencies, then Bayesian Binomial Test, with a Beta(1, 1) prior. The posterior 95% credible interval matches ours.
Reference class: Computed by TPG from the 1981, 1991, 1996, 2006 and 2016 selections as documented in the Wikipedia selection histories: early leaders won in 1991, 2006 and 2016 and were vetoed in 1981 and 1996. The 1991 straw poll lead (Boutros-Ghali) is from the same series.
Base rate
60%
of contested Secretary-General selections since 1981 (3 of 5) were won by the early leader in Council voting[10][11][12]
Computed by TPG from the 1981, 1991, 1996, 2006 and 2016 selections as documented in the Wikipedia selection histories: early leaders won in 1991, 2006 and 2016 and were vetoed in 1981 and 1996. The 1991 straw poll lead (Boutros-Ghali) is from the same series. (n = 5)
Closest historical parallels
1981 selection of Javier Perez de Cuellar (1981)
Alike: The last time the post went to Latin America, after the leading candidates were blocked by veto holders.
Outcome: After 16 deadlocked rounds, the Council turned to a dark horse who had not campaigned.
Where it breaks: In 1981 the vetoes were cast openly and repeatedly. In 2026 the vetoes are not yet visible on colour-coded ballots, but the U.S. has signalled through press reports that it wants new candidates, the closest the race has come to a 1981-style objection.
2016 selection of Antonio Guterres (2016)
Alike: A crowded, public field with candidate debates, straw polls and pressure for a woman and a particular region.
Outcome: Guterres led every round and was appointed by acclamation, even though the region favoured that year was Eastern Europe, not his own.
Where it breaks: Guterres never dropped below 11 encourage votes; Grynspan's support has moved between seven and ten across five polls (10, 7, 9, 10 and 9 by press accounts), a much weaker lead.
How it could play out
Every path we see, sized by probability. Paths where the frontrunner wins add up to 40%.
Grynspan clears the colour-coded rounds with no veto Yes40%
The U.S. does not cast a red discourage ballot against her on October 16 or after, in exchange for reform commitments.
Deadlock produces a late entrant No26%
Vetoes block the leaders and the Council turns to a new name, such as a U.S.-favoured reformer, as it did in 1981 and 1996.
Another declared candidate breaks through No25%
Grossi, Espinosa, Sall, Otunnu or A-Baki becomes the compromise after the leader is blocked, Grossi most likely if Russia and Britain do not veto him.
Rodrigues Birkett recovers and overtakes Grynspan No9%
A permanent member discourages Grynspan on a colour-coded ballot and Council members rally to Rodrigues Birkett as the Latin American fallback.
What would change our number
↑
The October 16 colour-coded straw poll shows Grynspan with no discourage from a permanent member
+25 points
↓
A permanent member's red discourage ballot appears against Grynspan on October 16 or later
-25 points
↓
Turkiye formally nominates Feridun Sinirlioglu, or another U.S.-backed candidate is formally nominated
-5 to -8 points
↓
Grossi shows no red discourage ballot while Grynspan shows one
-20 points for Grynspan, +15 for Grossi
↑
The U.S. publicly says it can support Grynspan
+15 points
TPG 40% vs Kalshi 54%
Read from Kalshi's public market data on October 15, 2026: Grynspan last traded at 54 cents, with a bid of 51 and an ask of 55, Grossi at 17 and Rodrigues Birkett at 9, an order we now match. We are 14 points lower on Grynspan because traders appear not to have priced the reporting that the U.S. cast one of her discourage votes and opposes the whole field. In 1981 and 1996 a single U.S. objection stopped the early leader, and the colour-coded ballot on October 16 is where an American veto would first become visible.
Market price recorded October 15, 2026 from Kalshi. Analysis, not investment advice.
How this question resolves
Resolves to the person the UN General Assembly appoints, on the recommendation of the Security Council, as Secretary-General for the term beginning January 1, 2027, succeeding Antonio Guterres. If no appointment is made by December 31, 2026, the question stays open and resolves to whoever is eventually appointed to succeed Guterres.
Closes: December 31, 2026. Judged by: UN General Assembly appointment resolution and UN press release, confirmed by wire reports
Questions people ask
Who will be the next UN Secretary-General?
+
As of October 15, 2026, TPG rates Rebeca Grynspan of Costa Rica, head of UNCTAD, the most likely next Secretary-General at 40 percent, down from 46. IAEA chief Rafael Grossi is second at 13 percent and Guyana's Carolyn Rodrigues Birkett third at 9, while a candidate not yet in the race is at 26 percent after reports that the U.S. opposes the whole field.
When is the next UN Secretary-General chosen?
+
Antonio Guterres's second term ends on December 31, 2026, and his successor takes office on January 1, 2027. The Security Council has held five secret straw polls, on July 30, August 21, September 18, September 29 and October 7. The first colour-coded ballot, which reveals vetoes, is scheduled for October 16. The Council then recommends one name, and the General Assembly formally appoints that person.
Will the next UN Secretary-General be from Latin America?
+
Probably, but less surely than a month ago. Under the informal rule that rotates the job among regional groups, a Latin American and Caribbean candidate is favoured this cycle, and the top three candidates in the latest straw poll all come from the region. As of October 15, 2026, our named candidates from the region sum to 68 percent (our calculation: 40 plus 13 plus 9 plus 4 plus 2), before any share of a late entrant.
Why did Michelle Bachelet drop out of the UN Secretary-General race?
+
The former Chilean president withdrew on September 19, 2026, a day after the third straw poll gave her one encourage vote and 11 discourage votes, down from six encourages in July. Chile's new government under President Jose Antonio Kast had withdrawn its support in March, and PassBlue reported the United States was the only Council member that never met with her.
Can the U.S. veto the UN Secretary-General pick?
+
Yes. Any of the five permanent Security Council members, the United States, China, Russia, Britain and France, can block a candidate. The United States did so in 1981 against Salim Ahmed Salim and in 1996 against Boutros Boutros-Ghali, who had 14 of 15 votes. Colour-coded ballots later in the process reveal which discourage votes come from veto holders.
Sources
Every source is dated on or before the October 15, 2026 evidence cutoff. Nothing published later was used.
“a former UN special representative for children and armed conflict, also received five encourage votes, along with seven discourage and three no opinions.”
“she received just one "encourage" vote, 11 "discourage" votes and three "no opinion" votes, compared with six encouraging votes in July and two in August.”
“Grynspan’s six discourage votes in the Oct. 7 straw poll were cast by the US and five elected members, including from Latin America, Africa and Europe.”
“the other nominees are Rafael Grossi, Carolyn Rodrigues Birkett, Olara Otunnu, Macky Sall, María Fernanda Espinosa and Ivonne A-Baki.”
Version history and integrity
Published forecasts are never edited. When the evidence changes we publish a new version beside the old one, each locked with a sha256 hash of its full contents. When this question resolves it is scored in public on our track record.