diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index db35c729..29a23d86 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -930,11 +930,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Calculation/Financial/CashFlow/Constant/Periodic/InterestAndPrincipal.php
 
-		-
-			message: "#^Parameter \\#4 \\$x2 of static method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\CashFlow\\\\Variable\\\\NonPeriodic\\:\\:xirrPart3\\(\\) expects float, mixed given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php
-
 		-
 			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\CashFlow\\\\Variable\\\\Periodic\\:\\:presentValue\\(\\) has parameter \\$args with no type specified\\.$#"
 			count: 1
@@ -7915,11 +7910,6 @@ parameters:
 			count: 1
 			path: tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XNpvTest.php
 
-		-
-			message: "#^Parameter \\#3 \\$message of static method PHPUnit\\\\Framework\\\\Assert\\:\\:assertEquals\\(\\) expects string, mixed given\\.$#"
-			count: 1
-			path: tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XirrTest.php
-
 		-
 			message: "#^Part \\$number \\(mixed\\) of encapsed string cannot be cast to string\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php b/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php
index 8986146c..d590e1a4 100644
--- a/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php
+++ b/src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/NonPeriodic.php
@@ -12,6 +12,8 @@ class NonPeriodic
 
     const FINANCIAL_PRECISION = 1.0e-08;
 
+    const DEFAULT_GUESS = 0.1;
+
     /**
      * XIRR.
      *
@@ -25,11 +27,11 @@ class NonPeriodic
      * @param mixed[] $dates      A series of payment dates
      *                                The first payment date indicates the beginning of the schedule of payments
      *                                All other dates must be later than this date, but they may occur in any order
-     * @param float $guess        An optional guess at the expected answer
+     * @param mixed $guess        An optional guess at the expected answer
      *
      * @return float|string
      */
-    public static function rate($values, $dates, $guess = 0.1)
+    public static function rate($values, $dates, $guess = self::DEFAULT_GUESS)
     {
         $rslt = self::xirrPart1($values, $dates);
         if ($rslt !== '') {
@@ -37,9 +39,13 @@ class NonPeriodic
         }
 
         // create an initial range, with a root somewhere between 0 and guess
-        $guess = Functions::flattenSingleValue($guess);
+        $guess = Functions::flattenSingleValue($guess) ?? self::DEFAULT_GUESS;
+        if (!is_numeric($guess)) {
+            return Functions::VALUE();
+        }
+        $guess = ($guess + 0.0) ?: self::DEFAULT_GUESS;
         $x1 = 0.0;
-        $x2 = $guess ?: 0.1;
+        $x2 = $guess + 0.0;
         $f1 = self::xnpvOrdered($x1, $values, $dates, false);
         $f2 = self::xnpvOrdered($x2, $values, $dates, false);
         $found = false;
@@ -54,9 +60,11 @@ class NonPeriodic
 
                 break;
             } elseif (abs($f1) < abs($f2)) {
-                $f1 = self::xnpvOrdered($x1 += 1.6 * ($x1 - $x2), $values, $dates, false);
+                $x1 += 1.6 * ($x1 - $x2);
+                $f1 = self::xnpvOrdered($x1, $values, $dates, false);
             } else {
-                $f2 = self::xnpvOrdered($x2 += 1.6 * ($x2 - $x1), $values, $dates, false);
+                $x2 += 1.6 * ($x2 - $x1);
+                $f2 = self::xnpvOrdered($x2, $values, $dates, false);
             }
         }
         if (!$found) {
@@ -104,11 +112,13 @@ class NonPeriodic
      */
     private static function xirrPart1(&$values, &$dates): string
     {
-        if (!is_array($values) && !is_array($dates)) {
-            return Functions::NA();
-        }
         $values = Functions::flattenArray($values);
         $dates = Functions::flattenArray($dates);
+        $valuesIsArray = count($values) > 1;
+        $datesIsArray = count($dates) > 1;
+        if (!$valuesIsArray && !$datesIsArray) {
+            return Functions::NA();
+        }
         if (count($values) != count($dates)) {
             return Functions::NAN();
         }
@@ -219,7 +229,11 @@ class NonPeriodic
             if (!is_numeric($dif)) {
                 return $dif;
             }
-            $xnpv += $values[$i] / (1 + $rate) ** ($dif / 365);
+            if ($rate <= -1.0) {
+                $xnpv += -abs($values[$i]) / (-1 - $rate) ** ($dif / 365);
+            } else {
+                $xnpv += $values[$i] / (1 + $rate) ** ($dif / 365);
+            }
         }
 
         return is_finite($xnpv) ? $xnpv : Functions::VALUE();
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/AllSetupTeardown.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/AllSetupTeardown.php
new file mode 100644
index 00000000..66ff4fc8
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/AllSetupTeardown.php
@@ -0,0 +1,116 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Financial;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception as CalcException;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Cell\DataType;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PHPUnit\Framework\TestCase;
+
+class AllSetupTeardown extends TestCase
+{
+    /**
+     * @var string
+     */
+    private $compatibilityMode;
+
+    /**
+     * @var ?Spreadsheet
+     */
+    private $spreadsheet;
+
+    /**
+     * @var ?Worksheet
+     */
+    private $sheet;
+
+    protected function setUp(): void
+    {
+        $this->compatibilityMode = Functions::getCompatibilityMode();
+    }
+
+    protected function tearDown(): void
+    {
+        Functions::setCompatibilityMode($this->compatibilityMode);
+        $this->sheet = null;
+        if ($this->spreadsheet !== null) {
+            $this->spreadsheet->disconnectWorksheets();
+            $this->spreadsheet = null;
+        }
+    }
+
+    protected static function setOpenOffice(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_OPENOFFICE);
+    }
+
+    protected static function setGnumeric(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_GNUMERIC);
+    }
+
+    /**
+     * @param mixed $expectedResult
+     */
+    protected function mightHaveException($expectedResult): void
+    {
+        if ($expectedResult === 'exception') {
+            $this->expectException(CalcException::class);
+        }
+    }
+
+    /**
+     * @param mixed $value
+     */
+    protected function setCell(string $cell, $value): void
+    {
+        if ($value !== null) {
+            if (is_string($value) && is_numeric($value)) {
+                $this->getSheet()->getCell($cell)->setValueExplicit($value, DataType::TYPE_STRING);
+            } else {
+                $this->getSheet()->getCell($cell)->setValue($value);
+            }
+        }
+    }
+
+    protected function getSpreadsheet(): Spreadsheet
+    {
+        if ($this->spreadsheet !== null) {
+            return $this->spreadsheet;
+        }
+        $this->spreadsheet = new Spreadsheet();
+
+        return $this->spreadsheet;
+    }
+
+    protected function getSheet(): Worksheet
+    {
+        if ($this->sheet !== null) {
+            return $this->sheet;
+        }
+        $this->sheet = $this->getSpreadsheet()->getActiveSheet();
+
+        return $this->sheet;
+    }
+
+    /**
+     * Adjust result if it is close enough to expected by ratio
+     *     rather than offset.
+     *
+     * @param mixed $result
+     * @param mixed $expectedResult
+     */
+    protected function adjustResult(&$result, $expectedResult): void
+    {
+        if (is_numeric($result) && is_numeric($expectedResult)) {
+            if ($expectedResult != 0) {
+                $frac = $result / $expectedResult;
+                if ($frac > 0.999999 && $frac < 1.000001) {
+                    $result = $expectedResult;
+                }
+            }
+        }
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XirrTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XirrTest.php
index a6677f3f..e5808a50 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XirrTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Financial/XirrTest.php
@@ -2,35 +2,60 @@
 
 namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Financial;
 
-use PhpOffice\PhpSpreadsheet\Calculation\Financial;
-use PhpOffice\PhpSpreadsheet\Calculation\Functions;
-use PHPUnit\Framework\TestCase;
-
-class XirrTest extends TestCase
+class XirrTest extends AllSetupTeardown
 {
-    protected function setUp(): void
-    {
-        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
-    }
-
     /**
      * @dataProvider providerXIRR
      *
      * @param mixed $expectedResult
-     * @param mixed $message
+     * @param string $message
+     * @param mixed $values
+     * @param mixed $dates
+     * @param mixed $guess
      */
-    public function testXIRR($expectedResult, $message, ...$args): void
+    public function testXIRR($expectedResult, $message, $values = null, $dates = null, $guess = null): void
     {
-        $result = Financial::XIRR(...$args);
-        if (is_numeric($result) && is_numeric($expectedResult)) {
-            if ($expectedResult != 0) {
-                $frac = $result / $expectedResult;
-                if ($frac > 0.999999 && $frac < 1.000001) {
-                    $result = $expectedResult;
+        $this->mightHaveException($expectedResult);
+        $sheet = $this->getSheet();
+        $formula = '=XIRR(';
+        if ($values !== null) {
+            if (is_array($values)) {
+                $row = 0;
+                foreach ($values as $value) {
+                    ++$row;
+                    $sheet->getCell("A$row")->setValue($value);
+                }
+                $formula .= "A1:A$row";
+            } else {
+                $sheet->getCell('A1')->setValue($values);
+                $formula .= 'A1';
+            }
+            if ($dates !== null) {
+                if (is_array($dates)) {
+                    $row = 0;
+                    foreach ($dates as $date) {
+                        ++$row;
+                        $sheet->getCell("B$row")->setValue($date);
+                    }
+                    $formula .= ",B1:B$row";
+                } else {
+                    $sheet->getCell('B1')->setValue($dates);
+                    $formula .= ',B1';
+                }
+                if ($guess !== null) {
+                    if ($guess !== 'C1') {
+                        $sheet->getCell('C1')->setValue($guess);
+                    }
+                    $formula .= ', C1';
                 }
             }
         }
-        self::assertEquals($expectedResult, $result, $message);
+        $formula .= ')';
+        $sheet->getCell('D1')->setValue($formula);
+        $result = $sheet->getCell('D1')->getCalculatedValue();
+        $this->adjustResult($result, $expectedResult);
+
+        self::assertEqualsWithDelta($expectedResult, $result, 0.1E-7, $message);
     }
 
     public function providerXIRR(): array
diff --git a/tests/data/Calculation/Financial/XIRR.php b/tests/data/Calculation/Financial/XIRR.php
index 3414d132..6b7a7b9a 100644
--- a/tests/data/Calculation/Financial/XIRR.php
+++ b/tests/data/Calculation/Financial/XIRR.php
@@ -59,6 +59,13 @@ return [
         '2015-01-04',
         0.1,
     ],
+    [
+        '#VALUE!',
+        'Return VALUE error if guess is non-numeric',
+        [1893.67, 139947.43, 52573.25, 48849.74, 26369.16, -273029.18],
+        ['2019-06-27', '2019-06-20', '2019-06-21', '2019-06-24', '2019-06-27', '2019-07-27'],
+        'XYZ',
+    ],
     [
         0.137963527441025,
         'Dates can be in any order after all',
@@ -118,10 +125,129 @@ return [
         ['2019-06-20', '2019-06-27', '2019-06-21', '2019-06-24', '2019-06-27', '2019-07-27'],
         0.00000,
     ],
+    [
+        0.13796353,
+        'Substitute when guess is empty cell',
+        [139947.43, 1893.67, 52573.25, 48849.74, 26369.16, -273029.18],
+        ['2019-06-20', '2019-06-27', '2019-06-21', '2019-06-24', '2019-06-27', '2019-07-27'],
+        'C1',
+    ],
     [
         '#NUM!',
         'Can\'t find a result2 that works after FINANCIAL_MAX_ITERATIONS tries, the #NUM! error value is returned',
         [-10000, 10000, -10000, 5],
         ['2010-01-15', '2010-04-16', '2010-07-16', '2010-10-15'],
     ],
+    [
+        -0.642307613,
+        'See issue #2469 - non-convergence with initial guess',
+        [55600, -51094.83],
+        ['2021-11-24', '2021-12-24'],
+    ],
+    [
+        -0.642307613,
+        'See issue #2469 - non-convergence with initial guess equal to correct answer',
+        [55600, -51094.83],
+        ['2021-11-24', '2021-12-24'],
+        -0.642307613,
+    ],
+    [
+        'exception',
+        'Only one argument should cause exception',
+        ['2021-11-24', '2021-12-24'],
+    ],
+    [
+        'exception',
+        'No argument should cause exception',
+    ],
+    [
+        0,
+        'DeCampo One year no growth',
+        [-1000, 1000],
+        ['2010-01-01', '2011-01-01'],
+    ],
+    [
+        0.1,
+        'DeCampo One year growth',
+        [-1000, 1100],
+        ['2010-01-01', '2011-01-01'],
+    ],
+    [
+        -0.1,
+        'DeCampo One year decline',
+        [-1000, 900],
+        ['2010-01-01', '2011-01-01'],
+    ],
+    [
+        0.1212676,
+        'DeCampo vs spreadsheet',
+        [-1000, -1000, -1000, -1000, 4300],
+        ['2010-01-01', '2010-04-01', '2010-07-01', '2010-10-01', '2011-01-01'],
+    ],
+    [
+        0.1212676,
+        'DeCampo vs spreadsheet reordered',
+        [-1000, 4300, -1000, -1000, -1000],
+        ['2010-10-01', '2011-01-01', '2010-07-01', '2010-01-01', '2010-04-01'],
+    ],
+    [
+        2.0,
+        'DeCampo Over 100% growth',
+        [-1000, 3000],
+        ['2010-01-01', '2011-01-01'],
+    ],
+    [
+        '#NUM!', // -1.0, DeCampo accounts for this case, Excel doesn't
+        'DeCampo Total loss one year, agree with Excel not DeCampo',
+        [-1000, 0],
+        ['2010-01-01', '2011-01-01'],
+    ],
+    [
+        '#NUM!', // -1.0, DeCampo accounts for this case, Excel doesn't
+        'DeCampo Total loss two years, agree with Excel not DeCampo',
+        [-1000, 0],
+        ['2010-01-01', '2012-01-01'],
+    ],
+    [
+        0.2504234710540838,
+        'DeCampo Readme example',
+        [-1000, -2500, -1000, 5050],
+        ['2016-01-15', '2016-02-08', '2016-04-17', '2016-08-24'],
+    ],
+    [
+        0.2126861,
+        'DeCampo from nodejs',
+        [-10000, 3027.25, 630.68, 2018.2, 1513.62, 1765.89, 4036.33, 4036.33, 1513.62, 1513.62, 2018.16, 1513.62, 1009.08, 1513.62, 1513.62, 1765.89, 1765.89, 22421.55],
+        ['2000-05-24', '2000-06-05', '2001-04-09', '2004-02-24', '2005-03-18', '2006-02-15', '2007-01-10', '2007-11-14', '2008-12-17', '2010-01-15', '2011-01-14', '2012-02-03', '2013-01-18', '2014-01-24', '2015-01-30', '2016-01-22', '2017-01-20', '2017-06-05'],
+    ],
+    [
+        '#NUM!', //-0.7640294,
+        'DeCampo issue5a, agree with Excel not DeCampo',
+        [-2610, -2589, -5110, -2550, -5086, -2561, -5040, -2552, -2530, 29520],
+        ['2001-06-22', '2001-07-03', '2001-07-05', '2001-07-06', '2001-07-09', '2001-07-10', '2001-07-12', '2001-07-13', '2001-07-16', '2001-07-17'],
+    ],
+    [
+        '#NUM!', //-0.8353404,
+        'DeCampo issue5b, agree with Excel not DeCampo',
+        [-2610, -2589, -5110, -2550, -5086, -2561, -5040, -2552, -2530, -9840, 38900],
+        ['2001-06-22', '2001-07-03', '2001-07-05', '2001-07-06', '2001-07-09', '2001-07-10', '2001-07-12', '2001-07-13', '2001-07-16', '2001-07-17', '2001-07-18'],
+    ],
+    [
+        412461.6383,
+        'Python XIRR test line 20',
+        [-100, 1000],
+        ['2019-12-31', '2020-03-05'],
+    ],
+    [
+        1.223853529e16,
+        'Python XIRR test line 21',
+        [-2236.3994659663, -47.3417585212, -46.52619316339632, 10424.74612565936, -13.077972551952],
+        ['2017-12-16', '2017-12-26', '2017-12-29', '2017-12-31', '2017-12-20'],
+    ],
+    [
+        '#NUM!', //-1,
+        'Python XIRR test line 39, agree with Excel not Python',
+        [18902, 83600, -5780, -4080, -56780, -2210, -2380, 33975, 23067.98, -1619.57],
+        ['2016-04-06', '2016-05-04', '2016-05-12', '2017-05-08', '2017-07-03', '2018-05-07', '2019-05-06', '2019-10-01', '2020-03-13', '2020-05-07'],
+    ],
 ];