diff --git a/poi/src/main/java/org/apache/poi/ss/formula/functions/Mirr.java b/poi/src/main/java/org/apache/poi/ss/formula/functions/Mirr.java
index ae4871ee78..e72f2ebf0e 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/functions/Mirr.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/functions/Mirr.java
@@ -56,10 +56,10 @@ public class Mirr extends MultiOperandNumericFunction {
     @Override
     protected double evaluate(double[] values) throws EvaluationException {
 
-        double financeRate = values[values.length-2];
-        double reinvestRate = values[values.length-1];
+        final double financeRate = values[values.length-2];
+        final double reinvestRate = values[values.length-1];
 
-        double[] mirrValues = Arrays.copyOf(values, values.length - 2);
+        final double[] mirrValues = Arrays.copyOf(values, values.length - 2);
 
         boolean mirrValuesAreAllNegatives = true;
         boolean mirrValuesAreAllPositives = true;
diff --git a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestMirr.java b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestMirr.java
index 0899e88907..69d9aa825d 100644
--- a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestMirr.java
+++ b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestMirr.java
@@ -112,6 +112,41 @@ final class TestMirr {
         assertEquals(0.18736225093, res, 0.00000001);
     }
 
+    @Test
+    void testMicrosoftSample() {
+        // https://support.microsoft.com/en-us/office/mirr-function-b020f038-7492-4fb4-93c1-35c345b53524
+        HSSFWorkbook wb = new HSSFWorkbook();
+        HSSFSheet sheet = wb.createSheet("Sheet1");
+
+        int row = 0;
+        sheet.createRow(row++).createCell(0).setCellValue("Data");
+        sheet.createRow(row++).createCell(0).setCellValue(-120000);
+        sheet.createRow(row++).createCell(0).setCellValue(39000);
+        sheet.createRow(row++).createCell(0).setCellValue(30000);
+        sheet.createRow(row++).createCell(0).setCellValue(21000);
+        sheet.createRow(row++).createCell(0).setCellValue(37000);
+        sheet.createRow(row++).createCell(0).setCellValue(46000);
+        sheet.createRow(row++).createCell(0).setCellValue(0.1);
+        sheet.createRow(row++).createCell(0).setCellValue(0.12);
+
+        HSSFFormulaEvaluator fe = new HSSFFormulaEvaluator(wb);
+        HSSFCell cell = sheet.createRow(row).createCell(0);
+        cell.setCellFormula("MIRR(A2:A7, A8, A9)");
+        fe.clearAllCachedResultValues();
+        fe.evaluateFormulaCell(cell);
+        assertEquals(0.126094, cell.getNumericCellValue(), 0.00000015);
+
+        cell.setCellFormula("MIRR(A2:A5, A8, A9)");
+        fe.clearAllCachedResultValues();
+        fe.evaluateFormulaCell(cell);
+        assertEquals(-0.048044655, cell.getNumericCellValue(), 0.00000015);
+
+        cell.setCellFormula("MIRR(A2:A7, A8, .14)");
+        fe.clearAllCachedResultValues();
+        fe.evaluateFormulaCell(cell);
+        assertEquals(0.134759111, cell.getNumericCellValue(), 0.00000015);
+    }
+
     @Test
     void testMirrFromSpreadsheet() {
         HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook("mirrTest.xls");