diff --git a/common/antes.ts b/common/antes.ts
index 979b9d87..c396edad 100644
--- a/common/antes.ts
+++ b/common/antes.ts
@@ -64,7 +64,7 @@ export function getAnteBets(
 
 export function getFreeAnswerAnte(
   creator: User,
-  contract: Contract<'MULTI'>,
+  contract: Contract,
   anteBetId: string
 ) {
   const { totalBets, totalShares } = contract
@@ -73,7 +73,7 @@ export function getFreeAnswerAnte(
 
   const { createdTime } = contract
 
-  const anteBet: Bet<'MULTI'> = {
+  const anteBet: Bet = {
     id: anteBetId,
     userId: creator.id,
     contractId: contract.id,
diff --git a/common/bet.ts b/common/bet.ts
index 96429fa2..7da4b18c 100644
--- a/common/bet.ts
+++ b/common/bet.ts
@@ -1,13 +1,10 @@
-export type Bet<outcomeType extends 'BINARY' | 'MULTI' = 'BINARY'> = {
+export type Bet = {
   id: string
   userId: string
   contractId: string
 
   amount: number // bet size; negative if SELL bet
-  outcome: {
-    BINARY: 'YES' | 'NO'
-    MULTI: string
-  }[outcomeType]
+  outcome: string
   shares: number // dynamic parimutuel pool weight; negative if SELL bet
 
   probBefore: number
diff --git a/common/calculate.ts b/common/calculate.ts
index b995bf4d..865d8caf 100644
--- a/common/calculate.ts
+++ b/common/calculate.ts
@@ -3,7 +3,8 @@ import { Bet } from './bet'
 import { Contract } from './contract'
 import { FEES } from './fees'
 
-export function getProbability(totalShares: { YES: number; NO: number }) {
+export function getProbability(totalShares: { [outcome: string]: number }) {
+  // For binary contracts only.
   return getOutcomeProbability(totalShares, 'YES')
 }
 
@@ -70,9 +71,9 @@ export function calculateRawShareValue(
   return currentValue - postSaleValue
 }
 
-export function calculateMoneyRatio<T extends 'BINARY' | 'MULTI'>(
-  contract: Contract<T>,
-  bet: Bet<T>,
+export function calculateMoneyRatio(
+  contract: Contract,
+  bet: Bet,
   shareValue: number
 ) {
   const { totalShares, totalBets, pool } = contract
@@ -115,11 +116,7 @@ export function calculateSaleAmount(contract: Contract, bet: Bet) {
   return deductFees(amount, winnings)
 }
 
-export function calculatePayout(
-  contract: Contract,
-  bet: Bet,
-  outcome: 'YES' | 'NO' | 'CANCEL' | 'MKT'
-) {
+export function calculatePayout(contract: Contract, bet: Bet, outcome: string) {
   if (outcome === 'CANCEL') return calculateCancelPayout(contract, bet)
   if (outcome === 'MKT') return calculateMktPayout(contract, bet)
 
@@ -182,7 +179,7 @@ function calculateMktPayout(contract: Contract, bet: Bet) {
   if (contract.outcomeType === 'BINARY')
     return calculateBinaryMktPayout(contract, bet)
 
-  const { totalShares, pool } = contract as any as Contract<'MULTI'>
+  const { totalShares, pool } = contract
 
   const totalPool = _.sum(Object.values(pool))
   const sharesSquareSum = _.sumBy(
@@ -206,16 +203,17 @@ function calculateMktPayout(contract: Contract, bet: Bet) {
 }
 
 function calculateBinaryMktPayout(contract: Contract, bet: Bet) {
+  const { resolutionProbability, totalShares, phantomShares } = contract
   const p =
-    contract.resolutionProbability !== undefined
-      ? contract.resolutionProbability
-      : getProbability(contract.totalShares)
+    resolutionProbability !== undefined
+      ? resolutionProbability
+      : getProbability(totalShares)
 
   const pool = contract.pool.YES + contract.pool.NO
 
   const weightedShareTotal =
-    p * (contract.totalShares.YES - contract.phantomShares.YES) +
-    (1 - p) * (contract.totalShares.NO - contract.phantomShares.NO)
+    p * (totalShares.YES - (phantomShares?.YES ?? 0)) +
+    (1 - p) * (totalShares.NO - (phantomShares?.NO ?? 0))
 
   const { outcome, amount, shares } = bet
 
diff --git a/common/contract.ts b/common/contract.ts
index b77f7606..c977fdff 100644
--- a/common/contract.ts
+++ b/common/contract.ts
@@ -1,4 +1,4 @@
-export type Contract<outcomeType extends 'BINARY' | 'MULTI' = 'BINARY'> = {
+export type Contract = {
   id: string
   slug: string // auto-generated; must be unique
 
@@ -13,29 +13,14 @@ export type Contract<outcomeType extends 'BINARY' | 'MULTI' = 'BINARY'> = {
   lowercaseTags: string[]
   visibility: 'public' | 'unlisted'
 
-  outcomeType: outcomeType
-  outcomes: {
-    BINARY: undefined
-    MULTI: 'FREE_ANSWER' | string[]
-  }[outcomeType]
+  outcomeType: 'BINARY' | 'MULTI'
+  outcomes?: 'FREE_ANSWER' | string[]
 
   mechanism: 'dpm-2'
-  phantomShares: {
-    BINARY: { YES: number; NO: number }
-    MULTI: undefined
-  }[outcomeType]
-  pool: {
-    BINARY: { YES: number; NO: number }
-    MULTI: { [answerId: string]: number }
-  }[outcomeType]
-  totalShares: {
-    BINARY: { YES: number; NO: number }
-    MULTI: { [answerId: string]: number }
-  }[outcomeType]
-  totalBets: {
-    BINARY: { YES: number; NO: number }
-    MULTI: { [answerId: string]: number }
-  }[outcomeType]
+  phantomShares?: { [outcome: string]: number }
+  pool: { [outcome: string]: number }
+  totalShares: { [outcome: string]: number }
+  totalBets: { [outcome: string]: number }
 
   createdTime: number // Milliseconds since epoch
   lastUpdatedTime: number // If the question or description was changed
@@ -43,14 +28,9 @@ export type Contract<outcomeType extends 'BINARY' | 'MULTI' = 'BINARY'> = {
 
   isResolved: boolean
   resolutionTime?: number // When the contract creator resolved the market
-  resolution?: {
-    BINARY: outcome
-    MULTI: string
-  }[outcomeType]
+  resolution?: string
   resolutionProbability?: number
 
   volume24Hours: number
   volume7Days: number
 }
-
-export type outcome = 'YES' | 'NO' | 'CANCEL' | 'MKT'
diff --git a/common/new-bet.ts b/common/new-bet.ts
index 78862b9d..29fd421a 100644
--- a/common/new-bet.ts
+++ b/common/new-bet.ts
@@ -61,7 +61,7 @@ export const getNewMultiBetInfo = (
   user: User,
   outcome: string,
   amount: number,
-  contract: Contract<'MULTI'>,
+  contract: Contract,
   newBetId: string
 ) => {
   const { pool, totalShares, totalBets } = contract
@@ -80,7 +80,7 @@ export const getNewMultiBetInfo = (
   const probBefore = getOutcomeProbability(totalShares, outcome)
   const probAfter = getOutcomeProbability(newTotalShares, outcome)
 
-  const newBet: Bet<'MULTI'> = {
+  const newBet: Bet = {
     id: newBetId,
     userId: user.id,
     contractId: contract.id,
diff --git a/common/new-contract.ts b/common/new-contract.ts
index bc4f1beb..c7b56c90 100644
--- a/common/new-contract.ts
+++ b/common/new-contract.ts
@@ -26,7 +26,7 @@ export function getNewContract(
       ? getBinaryProps(initialProb, ante)
       : getFreeAnswerProps(ante)
 
-  const contract: Contract<'BINARY' | 'MULTI'> = removeUndefinedProps({
+  const contract: Contract = removeUndefinedProps({
     id,
     slug,
     mechanism: 'dpm-2',
diff --git a/common/payouts.ts b/common/payouts.ts
index e68f58c8..0b917943 100644
--- a/common/payouts.ts
+++ b/common/payouts.ts
@@ -2,7 +2,7 @@ import * as _ from 'lodash'
 
 import { Bet } from './bet'
 import { deductFees, getProbability } from './calculate'
-import { Contract, outcome } from './contract'
+import { Contract } from './contract'
 import { CREATOR_FEE, FEES } from './fees'
 
 export const getCancelPayouts = (contract: Contract, bets: Bet[]) => {
@@ -100,7 +100,7 @@ export const getMktPayouts = (
 }
 
 export const getPayouts = (
-  outcome: outcome,
+  outcome: string,
   contract: Contract,
   bets: Bet[],
   resolutionProbability?: number
diff --git a/functions/src/create-answer.ts b/functions/src/create-answer.ts
index d8cc4a90..896dc953 100644
--- a/functions/src/create-answer.ts
+++ b/functions/src/create-answer.ts
@@ -42,7 +42,7 @@ export const createAnswer = functions.runWith({ minInstances: 1 }).https.onCall(
       const contractSnap = await transaction.get(contractDoc)
       if (!contractSnap.exists)
         return { status: 'error', message: 'Invalid contract' }
-      const contract = contractSnap.data() as Contract<'MULTI'>
+      const contract = contractSnap.data() as Contract
 
       if (
         contract.outcomeType !== 'MULTI' ||
diff --git a/functions/src/create-contract.ts b/functions/src/create-contract.ts
index bc02a0b8..18042768 100644
--- a/functions/src/create-contract.ts
+++ b/functions/src/create-contract.ts
@@ -100,7 +100,7 @@ export const createContract = functions
 
           const { yesBet, noBet } = getAnteBets(
             creator,
-            contract as Contract<'BINARY'>,
+            contract,
             yesBetDoc.id,
             noBetDoc.id
           )
@@ -116,11 +116,7 @@ export const createContract = functions
           const anteBetDoc = firestore
             .collection(`contracts/${contract.id}/bets`)
             .doc()
-          const anteBet = getFreeAnswerAnte(
-            creator,
-            contract as Contract<'MULTI'>,
-            anteBetDoc.id
-          )
+          const anteBet = getFreeAnswerAnte(creator, contract, anteBetDoc.id)
           await anteBetDoc.set(anteBet)
         }
       }
diff --git a/web/components/answers-panel.tsx b/web/components/answers-panel.tsx
index da30729f..ac2d643c 100644
--- a/web/components/answers-panel.tsx
+++ b/web/components/answers-panel.tsx
@@ -35,10 +35,7 @@ import { useAnswers } from '../hooks/use-answers'
 import { ResolveConfirmationButton } from './confirmation-button'
 import { tradingAllowed } from '../lib/firebase/contracts'
 
-export function AnswersPanel(props: {
-  contract: Contract<'MULTI'>
-  answers: Answer[]
-}) {
+export function AnswersPanel(props: { contract: Contract; answers: Answer[] }) {
   const { contract } = props
   const { creatorId, resolution } = contract
 
@@ -101,7 +98,7 @@ export function AnswersPanel(props: {
 
 function AnswerItem(props: {
   answer: Answer
-  contract: Contract<'MULTI'>
+  contract: Contract
   showChoice: boolean
   isChosen: boolean
   onChoose: () => void
@@ -209,7 +206,7 @@ function AnswerItem(props: {
 
 function AnswerBetPanel(props: {
   answer: Answer
-  contract: Contract<'MULTI'>
+  contract: Contract
   closePanel: () => void
 }) {
   const { answer, contract, closePanel } = props
@@ -267,14 +264,11 @@ function AnswerBetPanel(props: {
   const shares = calculateShares(contract.totalShares, betAmount ?? 0, answerId)
 
   const currentPayout = betAmount
-    ? calculatePayoutAfterCorrectBet(
-        contract as any as Contract,
-        {
-          outcome: answerId,
-          amount: betAmount,
-          shares,
-        } as Bet
-      )
+    ? calculatePayoutAfterCorrectBet(contract, {
+        outcome: answerId,
+        amount: betAmount,
+        shares,
+      } as Bet)
     : 0
 
   const currentReturn = betAmount ? (currentPayout - betAmount) / betAmount : 0
@@ -351,7 +345,7 @@ function AnswerBetPanel(props: {
   )
 }
 
-function CreateAnswerInput(props: { contract: Contract<'MULTI'> }) {
+function CreateAnswerInput(props: { contract: Contract }) {
   const { contract } = props
   const [text, setText] = useState('')
   const [betAmount, setBetAmount] = useState<number | undefined>(10)
@@ -426,7 +420,7 @@ function CreateAnswerInput(props: { contract: Contract<'MULTI'> }) {
 }
 
 function AnswerResolvePanel(props: {
-  contract: Contract<'MULTI'>
+  contract: Contract
   resolveOption: 'CHOOSE' | 'NONE' | 'CANCEL' | undefined
   setResolveOption: (option: 'CHOOSE' | 'NONE' | 'CANCEL' | undefined) => void
   answer: string | undefined
diff --git a/web/components/bet-panel.tsx b/web/components/bet-panel.tsx
index 3469b1c9..5eab2dd1 100644
--- a/web/components/bet-panel.tsx
+++ b/web/components/bet-panel.tsx
@@ -49,6 +49,7 @@ export function BetPanel(props: {
   }, [])
 
   const { contract, className, title, selected, onBetSuccess } = props
+  const { totalShares, phantomShares } = contract
 
   const user = useUser()
 
@@ -179,8 +180,8 @@ export function BetPanel(props: {
                 shares
               )} / ${formatWithCommas(
                 shares +
-                  contract.totalShares[betChoice] -
-                  contract.phantomShares[betChoice]
+                  totalShares[betChoice] -
+                  (phantomShares ? phantomShares[betChoice] : 0)
               )} ${betChoice} shares`}
             />
           </Row>
diff --git a/web/components/bets-list.tsx b/web/components/bets-list.tsx
index 657b35d3..514dd529 100644
--- a/web/components/bets-list.tsx
+++ b/web/components/bets-list.tsx
@@ -31,6 +31,7 @@ import {
 import { sellBet } from '../lib/firebase/api-call'
 import { ConfirmationButton } from './confirmation-button'
 import { OutcomeLabel, YesLabel, NoLabel } from './outcome-label'
+import { filterDefined } from '../../common/util/array'
 
 type BetSort = 'newest' | 'profit'
 
@@ -49,7 +50,7 @@ export function BetsList(props: { user: User }) {
     let disposed = false
     Promise.all(contractIds.map((id) => getContractFromId(id))).then(
       (contracts) => {
-        if (!disposed) setContracts(contracts.filter(Boolean) as Contract[])
+        if (!disposed) setContracts(filterDefined(contracts))
       }
     )
 
diff --git a/web/components/contract-feed.tsx b/web/components/contract-feed.tsx
index 4df451a2..ec7d68f1 100644
--- a/web/components/contract-feed.tsx
+++ b/web/components/contract-feed.tsx
@@ -21,7 +21,6 @@ import {
   contractPath,
   updateContract,
   tradingAllowed,
-  getBinaryProbPercent,
 } from '../lib/firebase/contracts'
 import { useUser } from '../hooks/use-user'
 import { Linkify } from './linkify'
@@ -38,7 +37,6 @@ import { useBets } from '../hooks/use-bets'
 import { Bet } from '../lib/firebase/bets'
 import { Comment, mapCommentsByBetId } from '../lib/firebase/comments'
 import { JoinSpans } from './join-spans'
-import { outcome } from '../../common/contract'
 import { fromNow } from '../lib/util/time'
 import BetRow from './bet-row'
 import { parseTags } from '../../common/util/parse'
@@ -382,7 +380,7 @@ function FeedDescription(props: { contract: Contract }) {
   )
 }
 
-function OutcomeIcon(props: { outcome?: outcome }) {
+function OutcomeIcon(props: { outcome?: string }) {
   const { outcome } = props
   switch (outcome) {
     case 'YES':
diff --git a/web/components/contract-prob-graph.tsx b/web/components/contract-prob-graph.tsx
index 13e6c48d..23daabfb 100644
--- a/web/components/contract-prob-graph.tsx
+++ b/web/components/contract-prob-graph.tsx
@@ -13,7 +13,9 @@ export function ContractProbGraph(props: { contract: Contract; bets: Bet[] }) {
 
   const bets = useBetsWithoutAntes(contract, props.bets)
 
-  const startProb = getProbability(phantomShares)
+  const startProb = getProbability(
+    phantomShares as { [outcome: string]: number }
+  )
 
   const times = bets
     ? [contract.createdTime, ...bets.map((bet) => bet.createdTime)].map(
diff --git a/web/lib/firebase/contracts.ts b/web/lib/firebase/contracts.ts
index a4231d52..88470a89 100644
--- a/web/lib/firebase/contracts.ts
+++ b/web/lib/firebase/contracts.ts
@@ -49,7 +49,7 @@ export function getBinaryProbPercent(contract: Contract) {
   return probPercent
 }
 
-export function tradingAllowed(contract: Contract<'BINARY' | 'MULTI'>) {
+export function tradingAllowed(contract: Contract) {
   return (
     !contract.isResolved &&
     (!contract.closeTime || contract.closeTime > Date.now())
@@ -84,9 +84,7 @@ export async function getContractFromSlug(slug: string) {
   const q = query(contractCollection, where('slug', '==', slug))
   const snapshot = await getDocs(q)
 
-  return snapshot.empty
-    ? undefined
-    : (snapshot.docs[0].data() as Contract<'BINARY' | 'MULTI'>)
+  return snapshot.empty ? undefined : (snapshot.docs[0].data() as Contract)
 }
 
 export async function deleteContract(contractId: string) {
diff --git a/web/pages/[username]/[contractSlug].tsx b/web/pages/[username]/[contractSlug].tsx
index 570aca01..fec1880d 100644
--- a/web/pages/[username]/[contractSlug].tsx
+++ b/web/pages/[username]/[contractSlug].tsx
@@ -186,7 +186,7 @@ function BetsSection(props: {
   )
 }
 
-const getOpenGraphProps = (contract: Contract<'BINARY'>) => {
+const getOpenGraphProps = (contract: Contract) => {
   const { resolution, question, creatorName, creatorUsername } = contract
   const probPercent = getBinaryProbPercent(contract)
 
diff --git a/web/pages/make-predictions.tsx b/web/pages/make-predictions.tsx
index 7af56478..3f37f535 100644
--- a/web/pages/make-predictions.tsx
+++ b/web/pages/make-predictions.tsx
@@ -26,7 +26,7 @@ type Prediction = {
 }
 
 function toPrediction(contract: Contract): Prediction {
-  const startProb = getProbability(contract.phantomShares)
+  const startProb = getProbability(contract.totalShares)
   return {
     question: contract.question,
     description: contract.description,