diff --git a/common/calculate.ts b/common/calculate.ts
index b5c6818b..2e69690e 100644
--- a/common/calculate.ts
+++ b/common/calculate.ts
@@ -174,7 +174,10 @@ export function calculatePayoutAfterCorrectBet(contract: Contract, bet: Bet) {
 }
 
 function calculateMktPayout(contract: Contract, bet: Bet) {
-  const p = getProbability(contract.totalShares)
+  const p =
+    contract.resolutionProbability !== undefined
+      ? contract.resolutionProbability
+      : getProbability(contract.totalShares)
 
   const weightedTotal =
     p * contract.totalBets.YES + (1 - p) * contract.totalBets.NO
diff --git a/common/contract.ts b/common/contract.ts
index d220da38..ed642cfa 100644
--- a/common/contract.ts
+++ b/common/contract.ts
@@ -27,6 +27,7 @@ export type Contract = {
   isResolved: boolean
   resolutionTime?: number // When the contract creator resolved the market
   resolution?: outcome // Chosen by creator; must be one of outcomes
+  resolutionProbability?: number
 
   volume24Hours: number
   volume7Days: number
diff --git a/common/payouts.ts b/common/payouts.ts
index 851861df..c4010ba2 100644
--- a/common/payouts.ts
+++ b/common/payouts.ts
@@ -59,8 +59,16 @@ export const getStandardPayouts = (
   ]) // add creator fee
 }
 
-export const getMktPayouts = (contract: Contract, bets: Bet[]) => {
-  const p = getProbability(contract.totalShares)
+export const getMktPayouts = (
+  contract: Contract,
+  bets: Bet[],
+  resolutionProbability?: number
+) => {
+  const p =
+    resolutionProbability === undefined
+      ? getProbability(contract.totalShares)
+      : resolutionProbability
+
   const poolTotal = contract.pool.YES + contract.pool.NO
   console.log('Resolved MKT at p=', p, 'pool: $M', poolTotal)
 
@@ -116,14 +124,15 @@ export const getMktPayouts = (contract: Contract, bets: Bet[]) => {
 export const getPayouts = (
   outcome: outcome,
   contract: Contract,
-  bets: Bet[]
+  bets: Bet[],
+  resolutionProbability?: number
 ) => {
   switch (outcome) {
     case 'YES':
     case 'NO':
       return getStandardPayouts(outcome, contract, bets)
     case 'MKT':
-      return getMktPayouts(contract, bets)
+      return getMktPayouts(contract, bets, resolutionProbability)
     case 'CANCEL':
       return getCancelPayouts(contract, bets)
   }
diff --git a/web/lib/util/format.ts b/common/util/format.ts
similarity index 100%
rename from web/lib/util/format.ts
rename to common/util/format.ts
diff --git a/functions/src/emails.ts b/functions/src/emails.ts
index 8650d981..63d0c9d2 100644
--- a/functions/src/emails.ts
+++ b/functions/src/emails.ts
@@ -1,5 +1,7 @@
+import { getProbability } from '../../common/calculate'
 import { Contract } from '../../common/contract'
 import { User } from '../../common/user'
+import { formatPercent } from '../../common/util/format'
 import { sendTemplateEmail } from './send-email'
 import { getPrivateUser, getUser } from './utils'
 
@@ -18,7 +20,8 @@ export const sendMarketResolutionEmail = async (
   payout: number,
   creator: User,
   contract: Contract,
-  resolution: 'YES' | 'NO' | 'CANCEL' | 'MKT'
+  resolution: 'YES' | 'NO' | 'CANCEL' | 'MKT',
+  resolutionProbability?: number
 ) => {
   const privateUser = await getPrivateUser(userId)
   if (
@@ -31,6 +34,14 @@ export const sendMarketResolutionEmail = async (
   const user = await getUser(userId)
   if (!user) return
 
+  const prob = resolutionProbability ?? getProbability(contract.totalShares)
+
+  const toDisplayResolution = {
+    YES: 'YES',
+    NO: 'NO',
+    CANCEL: 'N/A',
+    MKT: formatPercent(prob),
+  }
   const outcome = toDisplayResolution[resolution]
 
   const subject = `Resolved ${outcome}: ${contract.question}`
@@ -56,5 +67,3 @@ export const sendMarketResolutionEmail = async (
     templateData
   )
 }
-
-const toDisplayResolution = { YES: 'YES', NO: 'NO', CANCEL: 'N/A', MKT: 'MKT' }
diff --git a/functions/src/resolve-market.ts b/functions/src/resolve-market.ts
index df10feed..6816a8d7 100644
--- a/functions/src/resolve-market.ts
+++ b/functions/src/resolve-market.ts
@@ -16,17 +16,24 @@ export const resolveMarket = functions
       data: {
         outcome: 'YES' | 'NO' | 'CANCEL' | 'MKT'
         contractId: string
+        probabilityInt?: number
       },
       context
     ) => {
       const userId = context?.auth?.uid
       if (!userId) return { status: 'error', message: 'Not authorized' }
 
-      const { outcome, contractId } = data
+      const { outcome, contractId, probabilityInt } = data
 
       if (!['YES', 'NO', 'MKT', 'CANCEL'].includes(outcome))
         return { status: 'error', message: 'Invalid outcome' }
 
+      if (
+        probabilityInt !== undefined &&
+        (probabilityInt < 1 || probabilityInt > 99 || !isFinite(probabilityInt))
+      )
+        return { status: 'error', message: 'Invalid probability' }
+
       const contractDoc = firestore.doc(`contracts/${contractId}`)
       const contractSnap = await contractDoc.get()
       if (!contractSnap.exists)
@@ -42,10 +49,16 @@ export const resolveMarket = functions
       const creator = await getUser(contract.creatorId)
       if (!creator) return { status: 'error', message: 'Creator not found' }
 
+      const resolutionProbability =
+        probabilityInt !== undefined ? probabilityInt / 100 : undefined
+
       await contractDoc.update({
         isResolved: true,
         resolution: outcome,
         resolutionTime: Date.now(),
+        ...(resolutionProbability === undefined
+          ? {}
+          : { resolutionProbability }),
       })
 
       console.log('contract ', contractId, 'resolved to:', outcome)
@@ -57,7 +70,12 @@ export const resolveMarket = functions
       const bets = betsSnap.docs.map((doc) => doc.data() as Bet)
       const openBets = bets.filter((b) => !b.isSold && !b.sale)
 
-      const payouts = getPayouts(outcome, contract, openBets)
+      const payouts = getPayouts(
+        outcome,
+        contract,
+        openBets,
+        resolutionProbability
+      )
 
       console.log('payouts:', payouts)
 
@@ -79,7 +97,8 @@ export const resolveMarket = functions
         userPayouts,
         creator,
         contract,
-        outcome
+        outcome,
+        resolutionProbability
       )
 
       return result
@@ -91,7 +110,8 @@ const sendResolutionEmails = async (
   userPayouts: { [userId: string]: number },
   creator: User,
   contract: Contract,
-  outcome: 'YES' | 'NO' | 'CANCEL' | 'MKT'
+  outcome: 'YES' | 'NO' | 'CANCEL' | 'MKT',
+  resolutionProbability?: number
 ) => {
   const nonWinners = _.difference(
     _.uniq(openBets.map(({ userId }) => userId)),
@@ -103,7 +123,14 @@ const sendResolutionEmails = async (
   ]
   await Promise.all(
     emailPayouts.map(([userId, payout]) =>
-      sendMarketResolutionEmail(userId, payout, creator, contract, outcome)
+      sendMarketResolutionEmail(
+        userId,
+        payout,
+        creator,
+        contract,
+        outcome,
+        resolutionProbability
+      )
     )
   )
 }
diff --git a/web/components/amount-input.tsx b/web/components/amount-input.tsx
index 9968a132..f01ae418 100644
--- a/web/components/amount-input.tsx
+++ b/web/components/amount-input.tsx
@@ -1,6 +1,6 @@
 import clsx from 'clsx'
 import { useUser } from '../hooks/use-user'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 import { AddFundsButton } from './add-funds-button'
 import { Col } from './layout/col'
 import { Row } from './layout/row'
diff --git a/web/components/bet-panel.tsx b/web/components/bet-panel.tsx
index 12a094fb..5fd9b1f4 100644
--- a/web/components/bet-panel.tsx
+++ b/web/components/bet-panel.tsx
@@ -11,7 +11,7 @@ import {
   formatMoney,
   formatPercent,
   formatWithCommas,
-} from '../lib/util/format'
+} from '../../common/util/format'
 import { Title } from './title'
 import {
   getProbability,
diff --git a/web/components/bets-list.tsx b/web/components/bets-list.tsx
index 85a4fe71..5af4bb0d 100644
--- a/web/components/bets-list.tsx
+++ b/web/components/bets-list.tsx
@@ -11,7 +11,7 @@ import {
   formatMoney,
   formatPercent,
   formatWithCommas,
-} from '../lib/util/format'
+} from '../../common/util/format'
 import { Col } from './layout/col'
 import { Spacer } from './layout/spacer'
 import {
diff --git a/web/components/contract-card.tsx b/web/components/contract-card.tsx
index 9f91d272..e682c12a 100644
--- a/web/components/contract-card.tsx
+++ b/web/components/contract-card.tsx
@@ -1,7 +1,7 @@
 import clsx from 'clsx'
 import Link from 'next/link'
 import { Row } from '../components/layout/row'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 import { UserLink } from './user-page'
 import {
   Contract,
@@ -74,7 +74,7 @@ export function ResolutionOrChance(props: {
   const resolutionText = {
     YES: 'YES',
     NO: 'NO',
-    MKT: 'MKT',
+    MKT: probPercent,
     CANCEL: 'N/A',
     '': '',
   }[resolution || '']
diff --git a/web/components/contract-feed.tsx b/web/components/contract-feed.tsx
index c8618691..c5ae3ee5 100644
--- a/web/components/contract-feed.tsx
+++ b/web/components/contract-feed.tsx
@@ -27,7 +27,7 @@ import { Linkify } from './linkify'
 import { Row } from './layout/row'
 import { createComment } from '../lib/firebase/comments'
 import { useComments } from '../hooks/use-comments'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 import { ResolutionOrChance } from './contract-card'
 import { SiteLink } from './site-link'
 import { Col } from './layout/col'
diff --git a/web/components/create-fold-button.tsx b/web/components/create-fold-button.tsx
index c68f1223..794ed8ab 100644
--- a/web/components/create-fold-button.tsx
+++ b/web/components/create-fold-button.tsx
@@ -4,7 +4,7 @@ import { useState } from 'react'
 import { parseWordsAsTags } from '../../common/util/parse'
 import { createFold } from '../lib/firebase/api-call'
 import { foldPath } from '../lib/firebase/folds'
-import { toCamelCase } from '../lib/util/format'
+import { toCamelCase } from '../../common/util/format'
 import { ConfirmationButton } from './confirmation-button'
 import { Col } from './layout/col'
 import { Spacer } from './layout/spacer'
diff --git a/web/components/edit-fold-button.tsx b/web/components/edit-fold-button.tsx
index 64ffc2fe..3019f3a1 100644
--- a/web/components/edit-fold-button.tsx
+++ b/web/components/edit-fold-button.tsx
@@ -6,7 +6,7 @@ import { PencilIcon } from '@heroicons/react/outline'
 import { Fold } from '../../common/fold'
 import { parseWordsAsTags } from '../../common/util/parse'
 import { deleteFold, updateFold } from '../lib/firebase/folds'
-import { toCamelCase } from '../lib/util/format'
+import { toCamelCase } from '../../common/util/format'
 import { Spacer } from './layout/spacer'
 import { TagsList } from './tags-list'
 import { useRouter } from 'next/router'
diff --git a/web/components/outcome-label.tsx b/web/components/outcome-label.tsx
index 1eb8ac4f..ec65667d 100644
--- a/web/components/outcome-label.tsx
+++ b/web/components/outcome-label.tsx
@@ -5,7 +5,7 @@ export function OutcomeLabel(props: {
 
   if (outcome === 'YES') return <YesLabel />
   if (outcome === 'NO') return <NoLabel />
-  if (outcome === 'MKT') return <MarketLabel />
+  if (outcome === 'MKT') return <ProbLabel />
   return <CancelLabel />
 }
 
@@ -24,3 +24,7 @@ export function CancelLabel() {
 export function MarketLabel() {
   return <span className="text-blue-400">MKT</span>
 }
+
+export function ProbLabel() {
+  return <span className="text-blue-400">PROB</span>
+}
diff --git a/web/components/probability-selector.tsx b/web/components/probability-selector.tsx
new file mode 100644
index 00000000..2fc03787
--- /dev/null
+++ b/web/components/probability-selector.tsx
@@ -0,0 +1,36 @@
+import { Row } from './layout/row'
+
+export function ProbabilitySelector(props: {
+  probabilityInt: number
+  setProbabilityInt: (p: number) => void
+  isSubmitting?: boolean
+}) {
+  const { probabilityInt, setProbabilityInt, isSubmitting } = props
+
+  return (
+    <Row className="items-center gap-2">
+      <label className="input-group input-group-lg w-fit text-lg">
+        <input
+          type="number"
+          value={probabilityInt}
+          className="input input-bordered input-md text-lg"
+          disabled={isSubmitting}
+          min={1}
+          max={99}
+          onChange={(e) =>
+            setProbabilityInt(parseInt(e.target.value.substring(0, 2)))
+          }
+        />
+        <span>%</span>
+      </label>
+      <input
+        type="range"
+        className="range range-primary"
+        min={1}
+        max={99}
+        value={probabilityInt}
+        onChange={(e) => setProbabilityInt(parseInt(e.target.value))}
+      />
+    </Row>
+  )
+}
diff --git a/web/components/profile-menu.tsx b/web/components/profile-menu.tsx
index 94f2c3f6..327b389b 100644
--- a/web/components/profile-menu.tsx
+++ b/web/components/profile-menu.tsx
@@ -1,5 +1,5 @@
 import { firebaseLogout, User } from '../lib/firebase/users'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 import { Avatar } from './avatar'
 import { Col } from './layout/col'
 import { MenuButton } from './menu'
diff --git a/web/components/resolution-panel.tsx b/web/components/resolution-panel.tsx
index 64e643a3..1a409f7e 100644
--- a/web/components/resolution-panel.tsx
+++ b/web/components/resolution-panel.tsx
@@ -9,6 +9,8 @@ import { YesNoCancelSelector } from './yes-no-selector'
 import { Spacer } from './layout/spacer'
 import { ConfirmationButton as ConfirmationButton } from './confirmation-button'
 import { resolveMarket } from '../lib/firebase/api-call'
+import { ProbabilitySelector } from './probability-selector'
+import { getProbability } from '../../common/calculate'
 
 export function ResolutionPanel(props: {
   creator: User
@@ -26,6 +28,8 @@ export function ResolutionPanel(props: {
     'YES' | 'NO' | 'MKT' | 'CANCEL' | undefined
   >()
 
+  const [prob, setProb] = useState(getProbability(contract.totalShares) * 100)
+
   const [isSubmitting, setIsSubmitting] = useState(false)
   const [error, setError] = useState<string | undefined>(undefined)
 
@@ -35,6 +39,7 @@ export function ResolutionPanel(props: {
     const result = await resolveMarket({
       outcome,
       contractId: contract.id,
+      probabilityInt: prob,
     }).then((r) => r.data as any)
 
     console.log('resolved', outcome, 'result:', result)
@@ -82,8 +87,8 @@ export function ResolutionPanel(props: {
           <>The pool will be returned to traders with no fees.</>
         ) : outcome === 'MKT' ? (
           <>
-            Traders will be paid out at the current implied probability. You
-            earn 1% of the pool.
+            Traders will be paid out at the probability you specify. You earn 1%
+            of the pool.
           </>
         ) : (
           <>Resolving this market will immediately pay out traders.</>
@@ -113,7 +118,20 @@ export function ResolutionPanel(props: {
         }}
         onSubmit={resolve}
       >
-        <p>Are you sure you want to resolve this market?</p>
+        {outcome === 'MKT' ? (
+          <>
+            <p className="mb-4">
+              What probability would you like to resolve the market to?
+            </p>
+
+            <ProbabilitySelector
+              probabilityInt={Math.round(prob)}
+              setProbabilityInt={setProb}
+            />
+          </>
+        ) : (
+          <p>Are you sure you want to resolve this market?</p>
+        )}
       </ConfirmationButton>
     </Col>
   )
diff --git a/web/components/yes-no-selector.tsx b/web/components/yes-no-selector.tsx
index 8073ffe4..91cf6358 100644
--- a/web/components/yes-no-selector.tsx
+++ b/web/components/yes-no-selector.tsx
@@ -1,6 +1,6 @@
 import clsx from 'clsx'
 import React from 'react'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 import { Col } from './layout/col'
 import { Row } from './layout/row'
 
@@ -78,7 +78,7 @@ export function YesNoCancelSelector(props: {
           onClick={() => onSelect('MKT')}
           className={clsx(btnClassName, 'btn-sm')}
         >
-          MKT
+          PROB
         </Button>
 
         <Button
diff --git a/web/lib/firebase/contracts.ts b/web/lib/firebase/contracts.ts
index b74564d4..4789d19f 100644
--- a/web/lib/firebase/contracts.ts
+++ b/web/lib/firebase/contracts.ts
@@ -35,10 +35,11 @@ export function contractMetrics(contract: Contract) {
     createdTime,
     resolutionTime,
     isResolved,
+    resolutionProbability,
   } = contract
 
   const truePool = pool.YES + pool.NO
-  const prob = getProbability(totalShares)
+  const prob = resolutionProbability ?? getProbability(totalShares)
   const probPercent = Math.round(prob * 100) + '%'
 
   const startProb = getProbability(phantomShares)
diff --git a/web/lib/firebase/scoring.ts b/web/lib/firebase/scoring.ts
index 020a42ae..fa09d1c3 100644
--- a/web/lib/firebase/scoring.ts
+++ b/web/lib/firebase/scoring.ts
@@ -27,13 +27,18 @@ export function scoreTraders(contracts: Contract[], bets: Bet[][]) {
 }
 
 function scoreUsersByContract(contract: Contract, bets: Bet[]) {
-  const { resolution } = contract
+  const { resolution, resolutionProbability } = contract
 
   const [closedBets, openBets] = _.partition(
     bets,
     (bet) => bet.isSold || bet.sale
   )
-  const resolvePayouts = getPayouts(resolution ?? 'MKT', contract, openBets)
+  const resolvePayouts = getPayouts(
+    resolution ?? 'MKT',
+    contract,
+    openBets,
+    resolutionProbability
+  )
 
   const salePayouts = closedBets.map((bet) => {
     const { userId, sale } = bet
diff --git a/web/pages/create.tsx b/web/pages/create.tsx
index 42e7d44f..4cd8b352 100644
--- a/web/pages/create.tsx
+++ b/web/pages/create.tsx
@@ -15,6 +15,7 @@ import { InfoTooltip } from '../components/info-tooltip'
 import { CREATOR_FEE } from '../../common/fees'
 import { Page } from '../components/page'
 import { Title } from '../components/title'
+import { ProbabilitySelector } from '../components/probability-selector'
 
 export default function Create() {
   const [question, setQuestion] = useState('')
@@ -127,30 +128,11 @@ export function NewContract(props: { question: string; tag?: string }) {
         <label className="label">
           <span className="mb-1">Initial probability</span>
         </label>
-        <Row className="items-center gap-2">
-          <label className="input-group input-group-lg w-fit text-lg">
-            <input
-              type="number"
-              value={initialProb}
-              className="input input-bordered input-md text-lg"
-              disabled={isSubmitting}
-              min={1}
-              max={99}
-              onChange={(e) =>
-                setInitialProb(parseInt(e.target.value.substring(0, 2)))
-              }
-            />
-            <span>%</span>
-          </label>
-          <input
-            type="range"
-            className="range range-primary"
-            min={1}
-            max={99}
-            value={initialProb}
-            onChange={(e) => setInitialProb(parseInt(e.target.value))}
-          />
-        </Row>
+
+        <ProbabilitySelector
+          probabilityInt={initialProb}
+          setProbabilityInt={setInitialProb}
+        />
       </div>
 
       <Spacer h={4} />
diff --git a/web/pages/fold/[...slugs]/index.tsx b/web/pages/fold/[...slugs]/index.tsx
index 84b32465..5d4a07a6 100644
--- a/web/pages/fold/[...slugs]/index.tsx
+++ b/web/pages/fold/[...slugs]/index.tsx
@@ -28,7 +28,7 @@ import { useRouter } from 'next/router'
 import clsx from 'clsx'
 import { scoreCreators, scoreTraders } from '../../../lib/firebase/scoring'
 import { Leaderboard } from '../../../components/leaderboard'
-import { formatMoney, toCamelCase } from '../../../lib/util/format'
+import { formatMoney, toCamelCase } from '../../../../common/util/format'
 import { EditFoldButton } from '../../../components/edit-fold-button'
 import Custom404 from '../../404'
 import { FollowFoldButton } from '../../../components/follow-fold-button'
diff --git a/web/pages/leaderboards.tsx b/web/pages/leaderboards.tsx
index b131248c..e1d9c24c 100644
--- a/web/pages/leaderboards.tsx
+++ b/web/pages/leaderboards.tsx
@@ -1,9 +1,10 @@
 import _ from 'lodash'
+
 import { Col } from '../components/layout/col'
 import { Leaderboard } from '../components/leaderboard'
 import { Page } from '../components/page'
 import { getTopCreators, getTopTraders, User } from '../lib/firebase/users'
-import { formatMoney } from '../lib/util/format'
+import { formatMoney } from '../../common/util/format'
 
 export async function getStaticProps() {
   const [topTraders, topCreators] = await Promise.all([