diff --git a/common/loans.ts b/common/loans.ts
new file mode 100644
index 00000000..c07a7ba6
--- /dev/null
+++ b/common/loans.ts
@@ -0,0 +1,89 @@
+import { Dictionary, groupBy, sumBy, minBy } from 'lodash'
+import { Bet } from './bet'
+import { getContractBetMetrics } from './calculate'
+import { Contract, CPMMContract, FreeResponseContract, MultipleChoiceContract } from './contract'
+import { filterDefined } from './util/array'
+
+export const getUserLoanUpdates = (
+  bets: Bet[],
+  contractsById: Dictionary<Contract>
+) => {
+  const betsByContract = groupBy(bets, (bet) => bet.contractId)
+  const contracts = filterDefined(
+    Object.keys(betsByContract).map((contractId) => contractsById[contractId])
+  )
+
+  const betUpdates = filterDefined(
+    contracts
+      .map((c) => {
+        if (c.mechanism === 'cpmm-1') {
+          return getBinaryContractLoanUpdate(c, betsByContract[c.id])
+        } else if (
+          c.outcomeType === 'FREE_RESPONSE' ||
+          c.outcomeType === 'MULTIPLE_CHOICE'
+        )
+          return getFreeResponseContractLoanUpdate(c, betsByContract[c.id])
+        else {
+          // Unsupported contract / mechanism for loans.
+          return []
+        }
+      })
+      .flat()
+  )
+
+  const totalNewLoan = sumBy(betUpdates, (loanUpdate) => loanUpdate.loanTotal)
+
+  return {
+    totalNewLoan,
+    betUpdates,
+  }
+}
+
+const getBinaryContractLoanUpdate = (contract: CPMMContract, bets: Bet[]) => {
+  const { invested } = getContractBetMetrics(contract, bets)
+  const loanAmount = sumBy(bets, (bet) => bet.loanAmount ?? 0)
+  const oldestBet = minBy(bets, (bet) => bet.createdTime)
+
+  const newLoan = calculateNewLoan(invested, loanAmount)
+  if (isNaN(newLoan) || newLoan <= 0 || !oldestBet) return undefined
+
+  const loanTotal = (oldestBet.loanAmount ?? 0) + newLoan
+
+  return {
+    userId: oldestBet.userId,
+    contractId: contract.id,
+    betId: oldestBet.id,
+    newLoan,
+    loanTotal,
+  }
+}
+
+const getFreeResponseContractLoanUpdate = (
+  contract: FreeResponseContract | MultipleChoiceContract,
+  bets: Bet[]
+) => {
+  const openBets = bets.filter((bet) => bet.isSold || bet.sale)
+
+  return openBets.map((bet) => {
+    const loanAmount = bet.loanAmount ?? 0
+    const newLoan = calculateNewLoan(bet.amount, loanAmount)
+    const loanTotal = loanAmount + newLoan
+
+    if (isNaN(newLoan) || newLoan <= 0) return undefined
+
+    return {
+      userId: bet.userId,
+      contractId: contract.id,
+      betId: bet.id,
+      newLoan,
+      loanTotal,
+    }
+  })
+}
+
+const LOAN_WEEKLY_RATE = 0.05
+
+const calculateNewLoan = (investedValue: number, loanTotal: number) => {
+  const netValue = investedValue - loanTotal
+  return netValue * LOAN_WEEKLY_RATE
+}
\ No newline at end of file
diff --git a/functions/src/update-loans.ts b/functions/src/update-loans.ts
index 5536ece8..d6eb9f77 100644
--- a/functions/src/update-loans.ts
+++ b/functions/src/update-loans.ts
@@ -1,17 +1,12 @@
 import * as functions from 'firebase-functions'
 import * as admin from 'firebase-admin'
-import { Dictionary, groupBy, keyBy, minBy, sumBy } from 'lodash'
+import { groupBy, keyBy, sumBy } from 'lodash'
 import { getValues, log, payUser, writeAsync } from './utils'
 import { Bet } from '../../common/bet'
-import {
-  Contract,
-  CPMMContract,
-  FreeResponseContract,
-  MultipleChoiceContract,
-} from '../../common/contract'
+import { Contract } from '../../common/contract'
 import { PortfolioMetrics, User } from '../../common/user'
 import { filterDefined } from '../../common/util/array'
-import { getContractBetMetrics } from '../../common/calculate'
+import { getUserLoanUpdates } from '../../common/loans'
 import { createLoanIncomeNotification } from './create-notification'
 
 const firestore = admin.firestore()
@@ -112,87 +107,3 @@ const isUserEligibleForLoan = async (user: User) => {
   const { balance, investmentValue } = portfolio
   return balance + investmentValue > 0
 }
-
-const getUserLoanUpdates = (
-  bets: Bet[],
-  contractsById: Dictionary<Contract>
-) => {
-  const betsByContract = groupBy(bets, (bet) => bet.contractId)
-  const contracts = filterDefined(
-    Object.keys(betsByContract).map((contractId) => contractsById[contractId])
-  )
-
-  const betUpdates = filterDefined(
-    contracts
-      .map((c) => {
-        if (c.mechanism === 'cpmm-1') {
-          return getBinaryContractLoanUpdate(c, betsByContract[c.id])
-        } else if (
-          c.outcomeType === 'FREE_RESPONSE' ||
-          c.outcomeType === 'MULTIPLE_CHOICE'
-        )
-          return getFreeResponseContractLoanUpdate(c, betsByContract[c.id])
-        else {
-          // Unsupported contract / mechanism for loans.
-          return []
-        }
-      })
-      .flat()
-  )
-
-  const totalNewLoan = sumBy(betUpdates, (loanUpdate) => loanUpdate.loanTotal)
-
-  return {
-    totalNewLoan,
-    betUpdates,
-  }
-}
-
-const getBinaryContractLoanUpdate = (contract: CPMMContract, bets: Bet[]) => {
-  const { invested } = getContractBetMetrics(contract, bets)
-  const loanAmount = sumBy(bets, (bet) => bet.loanAmount ?? 0)
-  const oldestBet = minBy(bets, (bet) => bet.createdTime)
-
-  const newLoan = calculateNewLoan(invested, loanAmount)
-  if (isNaN(newLoan) || newLoan <= 0 || !oldestBet) return undefined
-
-  const loanTotal = (oldestBet.loanAmount ?? 0) + newLoan
-
-  return {
-    userId: oldestBet.userId,
-    contractId: contract.id,
-    betId: oldestBet.id,
-    newLoan,
-    loanTotal,
-  }
-}
-
-const getFreeResponseContractLoanUpdate = (
-  contract: FreeResponseContract | MultipleChoiceContract,
-  bets: Bet[]
-) => {
-  const openBets = bets.filter((bet) => bet.isSold || bet.sale)
-
-  return openBets.map((bet) => {
-    const loanAmount = bet.loanAmount ?? 0
-    const newLoan = calculateNewLoan(bet.amount, loanAmount)
-    const loanTotal = loanAmount + newLoan
-
-    if (isNaN(newLoan) || newLoan <= 0) return undefined
-
-    return {
-      userId: bet.userId,
-      contractId: contract.id,
-      betId: bet.id,
-      newLoan,
-      loanTotal,
-    }
-  })
-}
-
-const LOAN_WEEKLY_RATE = 0.05
-
-const calculateNewLoan = (investedValue: number, loanTotal: number) => {
-  const netValue = investedValue - loanTotal
-  return netValue * LOAN_WEEKLY_RATE
-}