diff --git a/.swiftlint.yml b/.swiftlint.yml
index 94e6336..1bc93db 100644
--- a/.swiftlint.yml
+++ b/.swiftlint.yml
@@ -10,7 +10,12 @@ empty_count:
 file_header:
   required_pattern: |
     \/\/
-    \/\/ {2}Copyright © \d{4} Tinder \(Match Group, LLC\)
+    \/\/ {2}All Contributions by Match Group
+    \/\/
+    \/\/ {2}Copyright © \d{4}(-\d{4})? Tinder \(Match Group, LLC\)
+    \/\/
+    \/\/ {2}Licensed under the Match Group Modified 3-Clause BSD License.
+    \/\/ {2}See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.
     \/\/
 
 private_over_fileprivate:
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..b2da94d
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,46 @@
+Modified 3-Clause BSD License
+
+Copyright © 2025 Match Group, LLC
+
+This license is based on the 3-Clause BSD license, modified for 
+clarity and to add the following requirements: Modifications must 
+be identified in any redistributions, any implied warranty of non 
+infringement is disclaimed, implied licenses are disclaimed, and you 
+agree that you are responsible for any claims that may arise out of 
+your use of the software.
+
+The copyright holder grants you permission to and use or redistribute 
+this software in source and binary forms, with or without modification, 
+conditioned on your acceptance of, and adherence to, the following 
+conditions:
+
+1. Redistributions of source code, whether or not modified, must 
+   retain the above copyright notice, this list of conditions, and the 
+   following disclaimer. If modified, the source code must identify 
+   the modifications (identification in general terms is acceptable).
+
+2. Redistributions in binary or application form must reproduce the 
+   above copyright notice, this list of conditions, and the following 
+   disclaimer in the documentation or other materials provided with 
+   the binary or application.
+
+3. You may not use the name of the copyright holder nor the names of 
+   the contributors to endorse or promote products derived from this 
+   software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+"AS IS" AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
+PARTICULAR PURPOSE, AND NON INFRINGEMENT ARE DISCLAIMED. IN NO EVENT 
+SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+POSSIBILITY OF SUCH DAMAGE. YOU AGREE TO INDEMNIFY AND HOLD HARMLESS 
+THE COPYRIGHT HOLDER AND ALL CONTRIBUTORS AGAINST ANY CLAIMS THAT 
+ARISE BASED ON YOUR USE, MODIFICATION, OR REDISTRIBUTION OF THIS 
+SOFTWARE. NO ADDITIONAL LICENSE BEYOND THOSE EXPRESSLY GRANTED ABOVE 
+ARE IMPLIED.
diff --git a/Makefile b/Makefile
index ef3e325..ab85709 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ fix:
 	@/usr/libexec/PlistBuddy -c \
 		"Delete :FILEHEADER" \
 		"$(XCSHAREDDATA)/IDETemplateMacros.plist" >/dev/null 2>&1 || true
-	@header=$$'\n//  Copyright © ___YEAR___ Tinder \(Match Group, LLC\)\n//'; \
+	@header=$$'\n//  All Contributions by Match Group\n//\n//  Copyright © ___YEAR___ Tinder \(Match Group, LLC\)\n//\n//  Licensed under the Match Group Modified 3-Clause BSD License.\n//  See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.\n//'; \
 	/usr/libexec/PlistBuddy -c \
 		"Add :FILEHEADER string $$header" \
 		"$(XCSHAREDDATA)/IDETemplateMacros.plist" >/dev/null 2>&1
diff --git a/README.md b/README.md
index 176e1d6..2ef26ef 100644
--- a/README.md
+++ b/README.md
@@ -112,3 +112,17 @@ cancellables.insert {
     publisherB.assign(to: \.keyPath, on: object)
 }
 ```
+
+## Contributing
+
+While interest in contributing to this project is appreciated, it has been open 
+sourced solely for the purpose of sharing with the community. This means we are 
+unable to accept outside contributions at this time and pull requests will not 
+be reviewed or merged. To report a security concern or vulnerability, please 
+submit a GitHub issue.
+
+## License
+
+Licensed under the [Match Group Modified 3-Clause BSD License](
+https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE
+).
diff --git a/Sources/CollectionBuilders/Array.swift b/Sources/CollectionBuilders/Array.swift
index bf99a37..cb95393 100644
--- a/Sources/CollectionBuilders/Array.swift
+++ b/Sources/CollectionBuilders/Array.swift
@@ -1,5 +1,10 @@
 //
-//  Copyright © 2023 Tinder (Match Group, LLC)
+//  All Contributions by Match Group
+//
+//  Copyright © 2025 Tinder (Match Group, LLC)
+//
+//  Licensed under the Match Group Modified 3-Clause BSD License.
+//  See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.
 //
 
 extension Array {
diff --git a/Sources/CollectionBuilders/Set.swift b/Sources/CollectionBuilders/Set.swift
index 6b85359..e0494d4 100644
--- a/Sources/CollectionBuilders/Set.swift
+++ b/Sources/CollectionBuilders/Set.swift
@@ -1,5 +1,10 @@
 //
-//  Copyright © 2023 Tinder (Match Group, LLC)
+//  All Contributions by Match Group
+//
+//  Copyright © 2025 Tinder (Match Group, LLC)
+//
+//  Licensed under the Match Group Modified 3-Clause BSD License.
+//  See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.
 //
 
 extension Set {
diff --git a/Tests/CollectionBuildersTests/ArrayTests.swift b/Tests/CollectionBuildersTests/ArrayTests.swift
index 9c114fb..7380078 100644
--- a/Tests/CollectionBuildersTests/ArrayTests.swift
+++ b/Tests/CollectionBuildersTests/ArrayTests.swift
@@ -1,5 +1,10 @@
 //
-//  Copyright © 2023 Tinder (Match Group, LLC)
+//  All Contributions by Match Group
+//
+//  Copyright © 2025 Tinder (Match Group, LLC)
+//
+//  Licensed under the Match Group Modified 3-Clause BSD License.
+//  See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.
 //
 
 import CollectionBuilders
diff --git a/Tests/CollectionBuildersTests/SetTests.swift b/Tests/CollectionBuildersTests/SetTests.swift
index 090a644..2ca7cc1 100644
--- a/Tests/CollectionBuildersTests/SetTests.swift
+++ b/Tests/CollectionBuildersTests/SetTests.swift
@@ -1,5 +1,10 @@
 //
-//  Copyright © 2023 Tinder (Match Group, LLC)
+//  All Contributions by Match Group
+//
+//  Copyright © 2025 Tinder (Match Group, LLC)
+//
+//  Licensed under the Match Group Modified 3-Clause BSD License.
+//  See https://github.com/Tinder/CollectionBuilders/blob/main/LICENSE for license information.
 //
 
 import CollectionBuilders