diff --git a/helpers/constants.ts b/helpers/constants.ts
index ea2ab8bc..708fe98d 100644
--- a/helpers/constants.ts
+++ b/helpers/constants.ts
@@ -4,6 +4,8 @@ import BigNumber from 'bignumber.js';
 // MATH
 // ----------------
 
+export const PERCENTAGE_FACTOR = '10000';
+export const HALF_PERCENTAGE = '5000';
 export const WAD = Math.pow(10, 18).toString();
 export const HALF_WAD = new BigNumber(WAD).multipliedBy(0.5).toString();
 export const RAY = new BigNumber(10).exponentiatedBy(27).toFixed();
diff --git a/test/configurator.spec.ts b/test/configurator.spec.ts
index 7d8a64d4..6a5dd66f 100644
--- a/test/configurator.spec.ts
+++ b/test/configurator.spec.ts
@@ -80,7 +80,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Unfreezes the ETH reserve', async () => {
@@ -107,7 +107,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Check the onlyAaveAdmin on freezeReserve ', async () => {
@@ -149,7 +149,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Activates the ETH reserve for borrowing', async () => {
@@ -177,7 +177,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
 
     expect(variableBorrowIndex.toString()).to.be.equal(RAY);
   });
@@ -222,7 +222,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(0);
     expect(liquidationBonus).to.be.equal(0);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Activates the ETH reserve as collateral', async () => {
@@ -249,7 +249,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Check the onlyAaveAdmin on configureReserveAsCollateral ', async () => {
@@ -285,7 +285,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(false);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Enables stable borrow rate on the ETH reserve', async () => {
@@ -311,7 +311,7 @@ makeSuite('LendingPoolConfigurator', (testEnv: TestEnv) => {
     expect(liquidationThreshold).to.be.equal(8000);
     expect(liquidationBonus).to.be.equal(10500);
     expect(stableBorrowRateEnabled).to.be.equal(true);
-    expect(reserveFactor).to.be.equal(0);
+    expect(reserveFactor).to.be.equal(1000);
   });
 
   it('Check the onlyAaveAdmin on disableReserveStableRate', async () => {
diff --git a/test/helpers/utils/calculations.ts b/test/helpers/utils/calculations.ts
index b334a7f1..db923176 100644
--- a/test/helpers/utils/calculations.ts
+++ b/test/helpers/utils/calculations.ts
@@ -5,10 +5,16 @@ import {
   MAX_UINT_AMOUNT,
   OPTIMAL_UTILIZATION_RATE,
   EXCESS_UTILIZATION_RATE,
+  PERCENTAGE_FACTOR,
 } from '../../../helpers/constants';
-import {IReserveParams, iAavePoolAssets, RateMode, tEthereumAddress} from '../../../helpers/types';
+import {
+  IReserveParams,
+  iAavePoolAssets,
+  RateMode,
+  tEthereumAddress,
+} from '../../../helpers/types';
 import './math';
-import {ReserveData, UserReserveData} from './interfaces';
+import { ReserveData, UserReserveData } from './interfaces';
 
 export const strToBN = (amount: string): BigNumber => new BigNumber(amount);
 
@@ -758,7 +764,7 @@ export const calcExpectedUserDataAfterSetUseAsCollateral = (
   userDataBeforeAction: UserReserveData,
   txCost: BigNumber
 ): UserReserveData => {
-  const expectedUserData = {...userDataBeforeAction};
+  const expectedUserData = { ...userDataBeforeAction };
 
   expectedUserData.usageAsCollateralEnabled = useAsCollateral;
 
@@ -885,7 +891,7 @@ export const calcExpectedUserDataAfterSwapRateMode = (
   txCost: BigNumber,
   txTimestamp: BigNumber
 ): UserReserveData => {
-  const expectedUserData = {...userDataBeforeAction};
+  const expectedUserData = { ...userDataBeforeAction };
 
   const stableDebtBalance = calcExpectedStableDebtTokenBalance(
     userDataBeforeAction.principalStableDebt,
@@ -1035,7 +1041,7 @@ export const calcExpectedUserDataAfterStableRateRebalance = (
   txCost: BigNumber,
   txTimestamp: BigNumber
 ): UserReserveData => {
-  const expectedUserData = {...userDataBeforeAction};
+  const expectedUserData = { ...userDataBeforeAction };
 
   expectedUserData.principalVariableDebt = calcExpectedVariableDebtTokenBalance(
     reserveDataBeforeAction,
@@ -1084,7 +1090,7 @@ export const calcExpectedATokenBalance = (
 ) => {
   const index = calcExpectedReserveNormalizedIncome(reserveData, currentTimestamp);
 
-  const {scaledATokenBalance: scaledBalanceBeforeAction} = userData;
+  const { scaledATokenBalance: scaledBalanceBeforeAction } = userData;
 
   return scaledBalanceBeforeAction.rayMul(index);
 };
@@ -1119,7 +1125,7 @@ export const calcExpectedVariableDebtTokenBalance = (
     currentTimestamp
   );
 
-  const {scaledVariableDebt} = userData;
+  const { scaledVariableDebt } = userData;
 
   return scaledVariableDebt.rayMul(normalizedDebt);
 };
@@ -1202,7 +1208,7 @@ export const calcExpectedInterestRates = (
   totalVariableDebt: BigNumber,
   averageStableBorrowRate: BigNumber
 ): BigNumber[] => {
-  const {reservesParams} = configuration;
+  const { reservesParams } = configuration;
 
   const reserveIndex = Object.keys(reservesParams).findIndex((value) => value === reserveSymbol);
   const [, reserveConfiguration] = (Object.entries(reservesParams) as [string, IReserveParams][])[
@@ -1248,7 +1254,9 @@ export const calcExpectedInterestRates = (
     variableBorrowRate,
     averageStableBorrowRate
   );
-  const liquidityRate = expectedOverallRate.rayMul(utilizationRate);
+  const liquidityRate = expectedOverallRate
+    .rayMul(utilizationRate)
+    .percentMul(new BigNumber(PERCENTAGE_FACTOR).minus(reserveConfiguration.reserveFactor));
 
   return [liquidityRate, stableBorrowRate, variableBorrowRate];
 };
@@ -1292,7 +1300,7 @@ const calcExpectedReserveNormalizedIncome = (
   reserveData: ReserveData,
   currentTimestamp: BigNumber
 ) => {
-  const {liquidityRate, liquidityIndex, lastUpdateTimestamp} = reserveData;
+  const { liquidityRate, liquidityIndex, lastUpdateTimestamp } = reserveData;
 
   //if utilization rate is 0, nothing to compound
   if (liquidityRate.eq('0')) {
diff --git a/test/helpers/utils/math.ts b/test/helpers/utils/math.ts
index df6165d2..66be629c 100644
--- a/test/helpers/utils/math.ts
+++ b/test/helpers/utils/math.ts
@@ -1,5 +1,5 @@
 import BigNumber from 'bignumber.js';
-import {RAY, WAD, HALF_RAY, HALF_WAD, WAD_RAY_RATIO} from '../../../helpers/constants';
+import {RAY, WAD, HALF_RAY, HALF_WAD, WAD_RAY_RATIO, HALF_PERCENTAGE, PERCENTAGE_FACTOR} from '../../../helpers/constants';
 
 declare module 'bignumber.js' {
   interface BigNumber {
@@ -7,10 +7,13 @@ declare module 'bignumber.js' {
     wad: () => BigNumber;
     halfRay: () => BigNumber;
     halfWad: () => BigNumber;
+    halfPercentage: () => BigNumber;
     wadMul: (a: BigNumber) => BigNumber;
     wadDiv: (a: BigNumber) => BigNumber;
     rayMul: (a: BigNumber) => BigNumber;
     rayDiv: (a: BigNumber) => BigNumber;
+    percentMul: (a: BigNumber) => BigNumber;
+    percentDiv: (a: BigNumber) => BigNumber;
     rayToWad: () => BigNumber;
     wadToRay: () => BigNumber;
   }
@@ -64,3 +67,20 @@ BigNumber.prototype.rayToWad = function (): BigNumber {
 BigNumber.prototype.wadToRay = function (): BigNumber {
   return this.multipliedBy(WAD_RAY_RATIO).decimalPlaces(0, BigNumber.ROUND_DOWN);
 };
+
+
+
+
+BigNumber.prototype.halfPercentage = (): BigNumber => {
+  return new BigNumber(HALF_PERCENTAGE).decimalPlaces(0, BigNumber.ROUND_DOWN);
+};
+
+BigNumber.prototype.percentMul = function (b: BigNumber): BigNumber {
+  return this.halfPercentage().plus(this.multipliedBy(b)).div(PERCENTAGE_FACTOR).decimalPlaces(0, BigNumber.ROUND_DOWN);
+};
+
+BigNumber.prototype.percentDiv = function (a: BigNumber): BigNumber {
+  const halfA = a.div(2).decimalPlaces(0, BigNumber.ROUND_DOWN);
+
+  return halfA.plus(this.multipliedBy(PERCENTAGE_FACTOR)).div(a).decimalPlaces(0, BigNumber.ROUND_DOWN);
+};
\ No newline at end of file