diff --git a/README.md b/README.md
index 2ab53ac..cb58212 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# SecId
+# SecID
 [![Gem Version](https://badge.fury.io/rb/sec_id.svg)](https://badge.fury.io/rb/sec_id)
 ![Build Status](https://github.com/svyatov/sec_id/actions/workflows/main.yml/badge.svg?branch=main)
 [![Maintainability](https://api.codeclimate.com/v1/badges/a4759963a5ddc4d55b24/maintainability)](https://codeclimate.com/github/svyatov/sec_id/maintainability)
@@ -45,11 +45,11 @@ Base API has 4 main methods which can be used both on class level and on instanc
 
   ```ruby
   # class level
-  SecId::ISIN.valid?('US5949181045') # => true
-  SecId::ISIN.valid?('US594918104')  # => false
+  SecID::ISIN.valid?('US5949181045') # => true
+  SecID::ISIN.valid?('US594918104')  # => false
 
   # instance level
-  isin = SecId::ISIN.new('US5949181045')
+  isin = SecID::ISIN.new('US5949181045')
   isin.valid? # => true
   ```
 
@@ -58,11 +58,11 @@ Base API has 4 main methods which can be used both on class level and on instanc
 
   ```ruby
   # class level
-  SecId::ISIN.valid_format?('US5949181045') # => true
-  SecId::ISIN.valid_format?('US594918104') # => true
+  SecID::ISIN.valid_format?('US5949181045') # => true
+  SecID::ISIN.valid_format?('US594918104') # => true
 
   # instance level
-  isin = SecId::ISIN.new('US594918104')
+  isin = SecID::ISIN.new('US594918104')
   isin.valid_format? # => true
   ```
 
@@ -71,10 +71,10 @@ Base API has 4 main methods which can be used both on class level and on instanc
 
   ```ruby
   # class level
-  SecId::ISIN.restore!('US594918104') # => 'US5949181045'
+  SecID::ISIN.restore!('US594918104') # => 'US5949181045'
 
   # instance level
-  isin = SecId::ISIN.new('US5949181045')
+  isin = SecID::ISIN.new('US5949181045')
   isin.restore! # => 'US5949181045'
   ```
 
@@ -86,10 +86,10 @@ Base API has 4 main methods which can be used both on class level and on instanc
 
   ```ruby
   # class level
-  SecId::ISIN.check_digit('US594918104') # => 5
+  SecID::ISIN.check_digit('US594918104') # => 5
 
   # instance level
-  isin = SecId::ISIN.new('US594918104')
+  isin = SecID::ISIN.new('US594918104')
   isin.calculate_check_digit # => 5
   isin.check_digit # => nil
   ```
@@ -98,17 +98,17 @@ Base API has 4 main methods which can be used both on class level and on instanc
   at instance level represents original check-digit of the number passed to `new`,
   which in this example is missing and thus it's `nil`.
 
-### SecId::ISIN full example
+### SecID::ISIN full example
 
 ```ruby
 # class level
-SecId::ISIN.valid?('US5949181045')       # => true
-SecId::ISIN.valid_format?('US594918104') # => true
-SecId::ISIN.restore!('US594918104')      # => 'US5949181045'
-SecId::ISIN.check_digit('US594918104')   # => 5
+SecID::ISIN.valid?('US5949181045')       # => true
+SecID::ISIN.valid_format?('US594918104') # => true
+SecID::ISIN.restore!('US594918104')      # => 'US5949181045'
+SecID::ISIN.check_digit('US594918104')   # => 5
 
 # instance level
-isin = SecId::ISIN.new('US5949181045')
+isin = SecID::ISIN.new('US5949181045')
 isin.full_number           # => 'US5949181045'
 isin.country_code          # => 'US'
 isin.nsin                  # => '594918104'
@@ -117,20 +117,20 @@ isin.valid?                # => true
 isin.valid_format?         # => true
 isin.restore!              # => 'US5949181045'
 isin.calculate_check_digit # => 5
-isin.to_cusip              # => #<SecId::CUSIP>
+isin.to_cusip              # => #<SecID::CUSIP>
 ```
 
-### SecId::CUSIP full example
+### SecID::CUSIP full example
 
 ```ruby
 # class level
-SecId::CUSIP.valid?('594918104')       # => true
-SecId::CUSIP.valid_format?('59491810') # => true
-SecId::CUSIP.restore!('59491810')      # => '594918104'
-SecId::CUSIP.check_digit('59491810')   # => 5
+SecID::CUSIP.valid?('594918104')       # => true
+SecID::CUSIP.valid_format?('59491810') # => true
+SecID::CUSIP.restore!('59491810')      # => '594918104'
+SecID::CUSIP.check_digit('59491810')   # => 5
 
 # instance level
-cusip = SecId::CUSIP.new('594918104')
+cusip = SecID::CUSIP.new('594918104')
 cusip.full_number           # => '594918104'
 cusip.cusip6                # => '594918'
 cusip.issue                 # => '10'
@@ -139,21 +139,21 @@ cusip.valid?                # => true
 cusip.valid_format?         # => true
 cusip.restore!              # => '594918104'
 cusip.calculate_check_digit # => 4
-cusip.to_isin('US')         # => #<SecId::ISIN>
+cusip.to_isin('US')         # => #<SecID::ISIN>
 cusip.cins?                 # => true
 ```
 
-### SecId::SEDOL full example
+### SecID::SEDOL full example
 
 ```ruby
 # class level
-SecId::SEDOL.valid?('B0Z52W5')       # => true
-SecId::SEDOL.valid_format?('B0Z52W') # => true
-SecId::SEDOL.restore!('B0Z52W')      # => 'B0Z52W5'
-SecId::SEDOL.check_digit('B0Z52W')   # => 5
+SecID::SEDOL.valid?('B0Z52W5')       # => true
+SecID::SEDOL.valid_format?('B0Z52W') # => true
+SecID::SEDOL.restore!('B0Z52W')      # => 'B0Z52W5'
+SecID::SEDOL.check_digit('B0Z52W')   # => 5
 
 # instance level
-cusip = SecId::SEDOL.new('B0Z52W5')
+cusip = SecID::SEDOL.new('B0Z52W5')
 cusip.full_number           # => 'B0Z52W5'
 cusip.check_digit           # => 5
 cusip.valid?                # => true
@@ -162,17 +162,17 @@ cusip.restore!              # => 'B0Z52W5'
 cusip.calculate_check_digit # => 5
 ```
 
-### SecId::FIGI full example
+### SecID::FIGI full example
 
 ```ruby
 # class level
-SecId::FIGI.valid?('BBG000DMBXR2')        # => true
-SecId::FIGI.valid_format?('BBG000DMBXR2') # => true
-SecId::FIGI.restore!('BBG000DMBXR')       # => 'BBG000DMBXR2'
-SecId::FIGI.check_digit('BBG000DMBXR')    # => 2
+SecID::FIGI.valid?('BBG000DMBXR2')        # => true
+SecID::FIGI.valid_format?('BBG000DMBXR2') # => true
+SecID::FIGI.restore!('BBG000DMBXR')       # => 'BBG000DMBXR2'
+SecID::FIGI.check_digit('BBG000DMBXR')    # => 2
 
 # instance level
-figi = SecId::FIGI.new('BBG000DMBXR2')
+figi = SecID::FIGI.new('BBG000DMBXR2')
 figi.full_number           # => 'BBG000DMBXR2'
 figi.prefix                # => 'BB'
 figi.random_part           # => '000DMBXR'
@@ -183,17 +183,17 @@ figi.restore!              # => 'BBG000DMBXR2'
 figi.calculate_check_digit # => 2
 ```
 
-### SecId::CIK full example
+### SecID::CIK full example
 
 ```ruby
 # class level
-SecId::CIK.valid?('0001094517')        # => true
-SecId::CIK.valid_format?('0001094517') # => true
-SecId::CIK.restore!('1094517')         # => '0001094517'
-SecId::CIK.check_digit('0001094517')   # raises NotImplementedError
+SecID::CIK.valid?('0001094517')        # => true
+SecID::CIK.valid_format?('0001094517') # => true
+SecID::CIK.restore!('1094517')         # => '0001094517'
+SecID::CIK.check_digit('0001094517')   # raises NotImplementedError
 
 # instance level
-cik = SecId::CIK.new('0001094517')
+cik = SecID::CIK.new('0001094517')
 cik.full_number           # => '0001094517'
 cik.padding               # => '000'
 cik.identifier            # => '1094517'
diff --git a/lib/sec_id.rb b/lib/sec_id.rb
index 2c80a64..ddd258a 100644
--- a/lib/sec_id.rb
+++ b/lib/sec_id.rb
@@ -9,7 +9,7 @@
 require 'sec_id/figi'
 require 'sec_id/cik'
 
-module SecId
+module SecID
   Error = Class.new(StandardError)
   InvalidFormatError = Class.new(Error)
 end
diff --git a/lib/sec_id/base.rb b/lib/sec_id/base.rb
index dd1f874..16857a3 100644
--- a/lib/sec_id/base.rb
+++ b/lib/sec_id/base.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   CHAR_TO_DIGITS = {
     '0' => 0,      '1' => 1,      '2' => 2,      '3' => 3,      '4' => 4,
     '5' => 5,      '6' => 6,      '7' => 7,      '8' => 8,      '9' => 9,
@@ -84,11 +84,11 @@ def parse(sec_id_number)
     end
 
     def char_to_digits(char)
-      SecId::CHAR_TO_DIGITS.fetch(char)
+      SecID::CHAR_TO_DIGITS.fetch(char)
     end
 
     def char_to_digit(char)
-      SecId::CHAR_TO_DIGIT.fetch(char)
+      SecID::CHAR_TO_DIGIT.fetch(char)
     end
 
     def mod10(sum)
diff --git a/lib/sec_id/cik.rb b/lib/sec_id/cik.rb
index fbe012e..7aadc46 100644
--- a/lib/sec_id/cik.rb
+++ b/lib/sec_id/cik.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   # https://en.wikipedia.org/wiki/Central_Index_Key
   class CIK < Base
     ID_REGEX = /\A
diff --git a/lib/sec_id/cusip.rb b/lib/sec_id/cusip.rb
index 3ebad01..fc092ba 100644
--- a/lib/sec_id/cusip.rb
+++ b/lib/sec_id/cusip.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   # https://en.wikipedia.org/wiki/CUSIP
   class CUSIP < Base
     ID_REGEX = /\A
diff --git a/lib/sec_id/figi.rb b/lib/sec_id/figi.rb
index 44714d6..e4bc2c5 100644
--- a/lib/sec_id/figi.rb
+++ b/lib/sec_id/figi.rb
@@ -2,7 +2,7 @@
 
 require 'set'
 
-module SecId
+module SecID
   class FIGI < Base
     ID_REGEX = /\A
       (?<identifier>
diff --git a/lib/sec_id/isin.rb b/lib/sec_id/isin.rb
index f664d1e..6369f77 100644
--- a/lib/sec_id/isin.rb
+++ b/lib/sec_id/isin.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   # https://en.wikipedia.org/wiki/International_Securities_Identification_Number
   class ISIN < Base
     ID_REGEX = /\A
diff --git a/lib/sec_id/sedol.rb b/lib/sec_id/sedol.rb
index dc946c5..a8c2c58 100644
--- a/lib/sec_id/sedol.rb
+++ b/lib/sec_id/sedol.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   # https://en.wikipedia.org/wiki/SEDOL
   class SEDOL < Base
     ID_REGEX = /\A
diff --git a/lib/sec_id/version.rb b/lib/sec_id/version.rb
index 1c1a1a3..4af4879 100644
--- a/lib/sec_id/version.rb
+++ b/lib/sec_id/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-module SecId
+module SecID
   VERSION = '4.1.0'
 end
diff --git a/sec_id.gemspec b/sec_id.gemspec
index 99304a3..0b9d7bd 100644
--- a/sec_id.gemspec
+++ b/sec_id.gemspec
@@ -6,7 +6,7 @@ require 'sec_id/version'
 
 Gem::Specification.new do |spec|
   spec.name          = 'sec_id'
-  spec.version       = SecId::VERSION
+  spec.version       = SecID::VERSION
   spec.authors       = ['Leonid Svyatov']
   spec.email         = ['leonid@svyatov.ru']
 
diff --git a/spec/sec_id/cik_spec.rb b/spec/sec_id/cik_spec.rb
index 2fb57b5..5de3ad7 100644
--- a/spec/sec_id/cik_spec.rb
+++ b/spec/sec_id/cik_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe SecId::CIK do
+RSpec.describe SecID::CIK do
   let(:cik) { described_class.new(cik_number) }
 
   context 'when CIK is valid' do
@@ -82,9 +82,9 @@
   describe '.restore!' do
     context 'when CIK is malformed' do
       it 'raises an error' do
-        expect { described_class.restore!('X9') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('0000000000') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('09876543210') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.restore!('X9') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('0000000000') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('09876543210') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
diff --git a/spec/sec_id/cusip_spec.rb b/spec/sec_id/cusip_spec.rb
index 7a651a3..4302d12 100644
--- a/spec/sec_id/cusip_spec.rb
+++ b/spec/sec_id/cusip_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe SecId::CUSIP do
+RSpec.describe SecID::CUSIP do
   let(:cusip) { described_class.new(cusip_number) }
 
   context 'when CUSIP is valid' do
@@ -76,7 +76,7 @@
       let(:cusip_number) { '02153X108' }
 
       it 'returns an ISIN' do
-        expect(cusip.to_isin('VI')).to be_a(SecId::ISIN)
+        expect(cusip.to_isin('VI')).to be_a(SecID::ISIN)
       end
     end
 
@@ -84,7 +84,7 @@
       let(:cusip_number) { '00B296YR7' }
 
       it 'raises an error' do
-        expect { cusip.to_isin('IE') }.to raise_error(SecId::InvalidFormatError)
+        expect { cusip.to_isin('IE') }.to raise_error(SecID::InvalidFormatError)
       end
     end
   end
@@ -110,8 +110,8 @@
   describe '.restore!' do
     context 'when CUSIP is incorrect' do
       it 'raises an error' do
-        expect { described_class.restore!('68389X1') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('68389X1055') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.restore!('68389X1') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('68389X1055') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
@@ -148,8 +148,8 @@
   describe '.check_digit' do
     context 'when CUSIP is incorrect' do
       it 'raises an error' do
-        expect { described_class.check_digit('9861913') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.check_digit('9861913025') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.check_digit('9861913') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.check_digit('9861913025') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
diff --git a/spec/sec_id/figi_spec.rb b/spec/sec_id/figi_spec.rb
index 78fc89f..8aa4393 100644
--- a/spec/sec_id/figi_spec.rb
+++ b/spec/sec_id/figi_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe SecId::FIGI do
+RSpec.describe SecID::FIGI do
   let(:figi) { described_class.new(figi_number) }
 
   context 'when FIGI is valid' do
@@ -45,7 +45,7 @@
 
     describe '#restore!' do
       it 'raises an error' do
-        expect { figi.restore! }.to raise_error(SecId::InvalidFormatError)
+        expect { figi.restore! }.to raise_error(SecID::InvalidFormatError)
       end
     end
   end
@@ -68,7 +68,7 @@
 
     describe '#restore!' do
       it 'raises an error' do
-        expect { figi.restore! }.to raise_error(SecId::InvalidFormatError)
+        expect { figi.restore! }.to raise_error(SecID::InvalidFormatError)
       end
     end
   end
@@ -119,9 +119,9 @@
   describe '.restore!' do
     context 'when FIGI is incorrect' do
       it 'raises an error' do
-        expect { described_class.restore!('BBG000HY4H') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('BBG000HY4HWX') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('BBG000HY4HW90') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.restore!('BBG000HY4H') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('BBG000HY4HWX') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('BBG000HY4HW90') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
@@ -170,9 +170,9 @@
   describe '.check_digit' do
     context 'when FIGI is incorrect' do
       it 'raises an error' do
-        expect { described_class.check_digit('BBG000HY4H') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.check_digit('BBG000HY4HWX') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.check_digit('BBG000HY4HW90') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.check_digit('BBG000HY4H') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.check_digit('BBG000HY4HWX') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.check_digit('BBG000HY4HW90') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
diff --git a/spec/sec_id/isin_spec.rb b/spec/sec_id/isin_spec.rb
index 7114ea2..39a8e48 100644
--- a/spec/sec_id/isin_spec.rb
+++ b/spec/sec_id/isin_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe SecId::ISIN do
+RSpec.describe SecID::ISIN do
   let(:isin) { described_class.new(isin_number) }
 
   context 'when ISIN is valid' do
@@ -45,7 +45,7 @@
 
     describe '#restore!' do
       it 'raises an error' do
-        expect { isin.restore! }.to raise_error(SecId::InvalidFormatError)
+        expect { isin.restore! }.to raise_error(SecID::InvalidFormatError)
       end
     end
   end
@@ -80,7 +80,7 @@
 
       it 'returns a CUSIP' do
         expect(isin.cgs?).to be(true)
-        expect(isin.to_cusip).to be_a(SecId::CUSIP)
+        expect(isin.to_cusip).to be_a(SecID::CUSIP)
       end
     end
 
@@ -89,7 +89,7 @@
 
       it 'raises an error' do
         expect(isin.cgs?).to be(false)
-        expect { isin.to_cusip }.to raise_error(SecId::InvalidFormatError)
+        expect { isin.to_cusip }.to raise_error(SecID::InvalidFormatError)
       end
     end
   end
@@ -122,8 +122,8 @@
   describe '.restore!' do
     context 'when ISIN is incorrect' do
       it 'raises an error' do
-        expect { described_class.restore!('US03783315') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('US03783315123') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.restore!('US03783315') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('US03783315123') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
@@ -160,8 +160,8 @@
   describe '.check_digit' do
     context 'when ISIN is incorrect' do
       it 'raises an error' do
-        expect { described_class.check_digit('US03783315') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.check_digit('US03783315123') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.check_digit('US03783315') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.check_digit('US03783315123') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
diff --git a/spec/sec_id/sedol_spec.rb b/spec/sec_id/sedol_spec.rb
index c406c1b..03e7759 100644
--- a/spec/sec_id/sedol_spec.rb
+++ b/spec/sec_id/sedol_spec.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-RSpec.describe SecId::SEDOL do
+RSpec.describe SecID::SEDOL do
   let(:sedol) { described_class.new(sedol_number) }
 
   context 'when SEDOL is valid' do
@@ -70,8 +70,8 @@
   describe '.restore!' do
     context 'when SEDOL is incorrect' do
       it 'raises an error' do
-        expect { described_class.restore!('I09CB4') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.restore!('B09CBL40') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.restore!('I09CB4') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.restore!('B09CBL40') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
@@ -108,8 +108,8 @@
   describe '.check_digit' do
     context 'when SEDOL is incorrect' do
       it 'raises an error' do
-        expect { described_class.check_digit('55U290') }.to raise_error(SecId::InvalidFormatError)
-        expect { described_class.check_digit('55290275') }.to raise_error(SecId::InvalidFormatError)
+        expect { described_class.check_digit('55U290') }.to raise_error(SecID::InvalidFormatError)
+        expect { described_class.check_digit('55290275') }.to raise_error(SecID::InvalidFormatError)
       end
     end
 
diff --git a/spec/sec_id_spec.rb b/spec/sec_id_spec.rb
index 4888b32..b7d33b2 100644
--- a/spec/sec_id_spec.rb
+++ b/spec/sec_id_spec.rb
@@ -2,8 +2,8 @@
 
 require 'spec_helper'
 
-RSpec.describe SecId do
+RSpec.describe SecID do
   it 'has a version number' do
-    expect(SecId::VERSION).not_to be_nil
+    expect(SecID::VERSION).not_to be_nil
   end
 end