diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 7102b5b04..58c4b8177 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -17,7 +17,7 @@ jobs:
     - uses: actions/checkout@v2
       with:
         submodules: true
-    - uses: actions/setup-node@v1
+    - uses: actions/setup-node@v3
       with:
         node-version: 18
     - run: npm install
diff --git a/index.bs b/index.bs
index 7202f89a8..a41a6431a 100644
--- a/index.bs
+++ b/index.bs
@@ -19,6 +19,7 @@ spec:infra; type:dfn; text:list
 spec:html; type:dfn; text:entangle
 spec:html; type:dfn; text:message port post message steps
 spec:html; type:dfn; text:port message queue
+spec:html; type:dfn; text:transferable objects
 </pre>
 
 <pre class="anchors">
@@ -593,7 +594,7 @@ callback UnderlyingSourceStartCallback = any (ReadableStreamController controlle
 callback UnderlyingSourcePullCallback = Promise<undefined> (ReadableStreamController controller);
 callback UnderlyingSourceCancelCallback = Promise<undefined> (optional any reason);
 
-enum ReadableStreamType { "bytes" };
+enum ReadableStreamType { "bytes", "owning" };
 </xmp>
 
 <dl>
@@ -661,8 +662,7 @@ enum ReadableStreamType { "bytes" };
    something more persistently wrong.
   </div>
 
- <dt><dfn dict-member for="UnderlyingSource" lt="type"><code>type</code></dfn> (byte streams
- only)</dt>
+ <dt><dfn dict-member for="UnderlyingSource" lt="type"><code>type</code></dfn></dt>
  <dd>
   <p>Can be set to "<dfn enum-value for="ReadableStreamType">bytes</dfn>" to signal that the
   constructed {{ReadableStream}} is a <a>readable byte stream</a>. This ensures that the resulting
@@ -673,8 +673,15 @@ enum ReadableStreamType { "bytes" };
   <p>For an example of how to set up a readable byte stream, including using the different
   controller interface, see [[#example-rbs-push]].
 
-  <p>Setting any value other than "{{ReadableStreamType/bytes}}" or undefined will cause the
-  {{ReadableStream()}} constructor to throw an exception.
+  <p>Can be set to "<dfn enum-value for="ReadableStreamType">owning</dfn>" to signal that the
+  constructed {{ReadableStream}} will own chunks (via transfer or serialization) before enqueuing them.
+  This ensures that enqueued chunks cannot be mutated by the source.
+  Chunks may have <dfn export>dispose steps</dfn> which are executed if enqueued chunks are dequeued
+  without being provided to the application, for instance when a {{ReadableStream}} is errored.
+  </p>
+
+  <p>Setting any value other than "{{ReadableStreamType/bytes}}", "{{ReadableStreamType/owning}}"
+  or undefined will cause the {{ReadableStream()}} constructor to throw an exception.
 
  <dt><dfn dict-member for="UnderlyingSource"
  lt="autoAllocateChunkSize"><code>autoAllocateChunkSize</code></dfn> (byte streams only)</dt>
@@ -831,7 +838,8 @@ option. If {{UnderlyingSource/type}} is set to undefined (including via omission
   1. Perform ? [$SetUpReadableByteStreamControllerFromUnderlyingSource$]([=this=],
      |underlyingSource|, |underlyingSourceDict|, |highWaterMark|).
  1. Otherwise,
-  1. Assert: |underlyingSourceDict|["{{UnderlyingSource/type}}"] does not [=map/exist=].
+  1. Assert: |underlyingSourceDict|["{{UnderlyingSource/type}}"] does not [=map/exist=] or
+     is "{{ReadableStreamType/owning}}".
   1. Let |sizeAlgorithm| be ! [$ExtractSizeAlgorithm$](|strategy|).
   1. Let |highWaterMark| be ? [$ExtractHighWaterMark$](|strategy|, 1).
   1. Perform ? [$SetUpReadableStreamDefaultControllerFromUnderlyingSource$]([=this=],
@@ -1518,7 +1526,7 @@ interface ReadableStreamDefaultController {
   readonly attribute unrestricted double? desiredSize;
 
   undefined close();
-  undefined enqueue(optional any chunk);
+  undefined enqueue(optional any chunk, optional StructuredSerializeOptions options = {});
   undefined error(optional any e);
 };
 </xmp>
@@ -1543,6 +1551,10 @@ the following table:
    <td class="non-normative">A boolean flag indicating whether the stream has been closed by its
    [=underlying source=], but still has [=chunks=] in its internal queue that have not yet been
    read
+  <tr>
+   <td><dfn>\[[isOwning]]</dfn>
+   <td class="non-normative">A boolean flag indicating whether to take ownership of enqueued chunks
+   via transfer or serialization.
   <tr>
    <td><dfn>\[[pullAgain]]</dfn>
    <td class="non-normative">A boolean flag set to true if the stream's mechanisms requested a call
@@ -1598,9 +1610,10 @@ the following table:
   previously-enqueued [=chunks=] from the stream, but once those are read, the stream will become
   closed.
 
- <dt><code><var ignore>controller</var>.{{ReadableStreamDefaultController/enqueue()|enqueue}}(<var ignore>chunk</var>)</code>
+ <dt><code><var ignore>controller</var>.{{ReadableStreamDefaultController/enqueue()|enqueue}}(|chunk|, |options|)</code>
  <dd>
-  <p>Enqueues the given [=chunk=] <var ignore>chunk</var> in the controlled readable stream.
+  <p>Enqueues the given [=chunk=] |chunk| in the controlled readable stream,
+    with |options|.
 
  <dt><code><var ignore>controller</var>.{{ReadableStreamDefaultController/error()|error}}(<var ignore>e</var>)</code>
  <dd>
@@ -1626,11 +1639,14 @@ the following table:
 
 <div algorithm>
  The <dfn id="rs-default-controller-enqueue" method
- for="ReadableStreamDefaultController">enqueue(|chunk|)</dfn> method steps are:
+ for="ReadableStreamDefaultController">enqueue(|chunk|, |options|)</dfn> method steps are:
 
+ 1. Let |transferList| be |options|["transfer"].
+ 1. If |transferList| is not [=list/is empty|empty=] and [=this=].[=ReadableStreamDefaultController/[[isOwning]]=] is false,
+    throw a {{TypeError}} exception.
  1. If ! [$ReadableStreamDefaultControllerCanCloseOrEnqueue$]([=this=]) is false, throw a
     {{TypeError}} exception.
- 1. Perform ? [$ReadableStreamDefaultControllerEnqueue$]([=this=], |chunk|).
+ 1. Perform ? [$ReadableStreamDefaultControllerEnqueue$]([=this=], |chunk|, |transferList|).
 </div>
 
 <div algorithm>
@@ -2200,7 +2216,7 @@ The following abstract operations operate on {{ReadableStream}} instances at a h
    1. Otherwise:
     1. Let |value| be ? [$IteratorValue$](|iterResult|).
     1. Perform ! [$ReadableStreamDefaultControllerEnqueue$](|stream|.[=ReadableStream/[[controller]]=],
-       |value|).
+       |value|, « »).
        <!-- TODO (future): If we allow changing the queuing strategy, this Enqueue might throw.
              We'll then need to catch the error and close the async iterator. -->
  1. Let |cancelAlgorithm| be the following steps, given |reason|:
@@ -2362,8 +2378,8 @@ create them does not matter.
  objects|transferring=] their [=chunks=]. However, it does introduce a noticeable asymmetry between
  the two branches, and limits the possible [=chunks=] to serializable ones. [[!HTML]]
 
- If |stream| is a [=readable byte stream=], then |cloneForBranch2| is ignored and chunks are cloned
- unconditionally.
+ If |stream| is a [=readable byte stream=], or if |stream| type is "{{ReadableStreamType/owning}}",
+ then |cloneForBranch2| is ignored and chunks are cloned unconditionally.
 
  <p class="note">In this standard ReadableStreamTee is always called with |cloneForBranch2| set to
  false; other specifications pass true via the [=ReadableStream/tee=] wrapper algorithm.
@@ -2374,6 +2390,8 @@ create them does not matter.
  1. Assert: |cloneForBranch2| is a boolean.
  1. If |stream|.[=ReadableStream/[[controller]]=] [=implements=] {{ReadableByteStreamController}},
     return ? [$ReadableByteStreamTee$](|stream|).
+ 1. If |stream|.[=ReadableStream/[[controller]]=].[=ReadableStreamDefaultController/[[isOwning]]=]
+    is true, return ? [$ReadableStreamDefaultTee$](|stream|, true).
  1. Return ? [$ReadableStreamDefaultTee$](|stream|, |cloneForBranch2|).
 </div>
 
@@ -2414,10 +2432,10 @@ create them does not matter.
       1. Otherwise, set |chunk2| to |cloneResult|.\[[Value]].
      1. If |canceled1| is false, perform !
         [$ReadableStreamDefaultControllerEnqueue$](|branch1|.[=ReadableStream/[[controller]]=],
-        |chunk1|).
+        |chunk1|, « »).
      1. If |canceled2| is false, perform !
         [$ReadableStreamDefaultControllerEnqueue$](|branch2|.[=ReadableStream/[[controller]]=],
-        |chunk2|).
+        |chunk2|, « »).
      1. Set |reading| to false.
      1. If |readAgain| is true, perform |pullAlgorithm|.
 
@@ -3077,13 +3095,21 @@ The following abstract operations support the implementation of the
 <div algorithm>
  <dfn abstract-op lt="ReadableStreamDefaultControllerEnqueue"
  id="readable-stream-default-controller-enqueue">ReadableStreamDefaultControllerEnqueue(|controller|,
- |chunk|)</dfn> performs the following steps:
+ |chunk|, |transferList|)</dfn> performs the following steps:
 
+ 1. Assert: |transferList| [=list/is empty=] or |controller|.[=ReadableStreamDefaultController/[[isOwning]]=] is true.
  1. If ! [$ReadableStreamDefaultControllerCanCloseOrEnqueue$](|controller|) is false, return.
  1. Let |stream| be |controller|.[=ReadableStreamDefaultController/[[stream]]=].
  1. If ! [$IsReadableStreamLocked$](|stream|) is true and !
-    [$ReadableStreamGetNumReadRequests$](|stream|) > 0, perform !
-    [$ReadableStreamFulfillReadRequest$](|stream|, |chunk|, false).
+    [$ReadableStreamGetNumReadRequests$](|stream|) > 0, perform the following steps:
+    1. Let |internalChunk| be |chunk|.
+    1. If |controller|.[=ReadableStreamDefaultController/[[isOwning]]=] is true, perform the following steps:
+       1. Let |result| be [$StructuredTransferOrClone$](|chunk|, |transferList|).
+       1. If |result| is an abrupt completion,
+          1. Perform ! [$ReadableStreamDefaultControllerError$](|controller|, |result|.\[[Value]]).
+          1. Return |result|.
+       1. Set |internalChunk| to |result|.\[[Value]].
+    1. Perform ! [$ReadableStreamFulfillReadRequest$](|stream|, |internalChunk|, false).
  1. Otherwise,
   1. Let |result| be the result of performing
      |controller|.[=ReadableStreamDefaultController/[[strategySizeAlgorithm]]=], passing in |chunk|,
@@ -3092,7 +3118,7 @@ The following abstract operations support the implementation of the
    1. Perform ! [$ReadableStreamDefaultControllerError$](|controller|, |result|.\[[Value]]).
    1. Return |result|.
   1. Let |chunkSize| be |result|.\[[Value]].
-  1. Let |enqueueResult| be [$EnqueueValueWithSize$](|controller|, |chunk|, |chunkSize|).
+  1. Let |enqueueResult| be [$EnqueueValueWithSize$](|controller|, |chunk|, |chunkSize|, |transferList|).
   1. If |enqueueResult| is an abrupt completion,
    1. Perform ! [$ReadableStreamDefaultControllerError$](|controller|, |enqueueResult|.\[[Value]]).
    1. Return |enqueueResult|.
@@ -3156,7 +3182,7 @@ The following abstract operations support the implementation of the
  <dfn abstract-op lt="SetUpReadableStreamDefaultController"
  id="set-up-readable-stream-default-controller">SetUpReadableStreamDefaultController(|stream|,
  |controller|, |startAlgorithm|, |pullAlgorithm|, |cancelAlgorithm|, |highWaterMark|,
- |sizeAlgorithm|)</dfn> performs the following steps:
+ |sizeAlgorithm|, |isOwning|)</dfn> performs the following steps:
 
  1. Assert: |stream|.[=ReadableStream/[[controller]]=] is undefined.
  1. Set |controller|.[=ReadableStreamDefaultController/[[stream]]=] to |stream|.
@@ -3166,8 +3192,9 @@ The following abstract operations support the implementation of the
     |controller|.[=ReadableStreamDefaultController/[[pullAgain]]=], and
     |controller|.[=ReadableStreamDefaultController/[[pulling]]=] to false.
  1. Set |controller|.[=ReadableStreamDefaultController/[[strategySizeAlgorithm]]=] to
-    |sizeAlgorithm| and |controller|.[=ReadableStreamDefaultController/[[strategyHWM]]=] to
-    |highWaterMark|.
+    |sizeAlgorithm|, |controller|.[=ReadableStreamDefaultController/[[strategyHWM]]=] to
+    |highWaterMark| and |controller|.[=ReadableStreamDefaultController/[[isOwning]]=] to
+    |isOwning|.
  1. Set |controller|.[=ReadableStreamDefaultController/[[pullAlgorithm]]=] to |pullAlgorithm|.
  1. Set |controller|.[=ReadableStreamDefaultController/[[cancelAlgorithm]]=] to |cancelAlgorithm|.
  1. Set |stream|.[=ReadableStream/[[controller]]=] to |controller|.
@@ -3192,6 +3219,8 @@ The following abstract operations support the implementation of the
  1. Let |startAlgorithm| be an algorithm that returns undefined.
  1. Let |pullAlgorithm| be an algorithm that returns [=a promise resolved with=] undefined.
  1. Let |cancelAlgorithm| be an algorithm that returns [=a promise resolved with=] undefined.
+ 1. Let |isOwning| be true if |underlyingSourceDict|["{{UnderlyingSource/type}}"] is
+    "{{ReadableStreamType/owning}}" and false otherwise.
  1. If |underlyingSourceDict|["{{UnderlyingSource/start}}"] [=map/exists=], then set
     |startAlgorithm| to an algorithm which returns the result of [=invoking=]
     |underlyingSourceDict|["{{UnderlyingSource/start}}"] with argument list
@@ -3205,7 +3234,7 @@ The following abstract operations support the implementation of the
     [=invoking=] |underlyingSourceDict|["{{UnderlyingSource/cancel}}"] with argument list
     «&nbsp;|reason|&nbsp;» and [=callback this value=] |underlyingSource|.
  1. Perform ? [$SetUpReadableStreamDefaultController$](|stream|, |controller|, |startAlgorithm|,
-    |pullAlgorithm|, |cancelAlgorithm|, |highWaterMark|, |sizeAlgorithm|).
+    |pullAlgorithm|, |cancelAlgorithm|, |highWaterMark|, |sizeAlgorithm|, |isOwning|).
 </div>
 
 <h4 id="rbs-controller-abstract-ops">Byte stream controllers</h4>
@@ -5351,7 +5380,7 @@ The following abstract operations support the implementation of the
  id="writable-stream-default-controller-close">WritableStreamDefaultControllerClose(|controller|)</dfn>
  performs the following steps:
 
- 1. Perform ! [$EnqueueValueWithSize$](|controller|, [=close sentinel=], 0).
+ 1. Perform ! [$EnqueueValueWithSize$](|controller|, [=close sentinel=], 0, « »).
  1. Perform ! [$WritableStreamDefaultControllerAdvanceQueueIfNeeded$](|controller|).
 </div>
 
@@ -5455,7 +5484,7 @@ The following abstract operations support the implementation of the
  id="writable-stream-default-controller-write">WritableStreamDefaultControllerWrite(|controller|,
  |chunk|, |chunkSize|)</dfn> performs the following steps:
 
- 1. Let |enqueueResult| be [$EnqueueValueWithSize$](|controller|, |chunk|, |chunkSize|).
+ 1. Let |enqueueResult| be [$EnqueueValueWithSize$](|controller|, |chunk|, |chunkSize|, « »).
  1. If |enqueueResult| is an abrupt completion,
   1. Perform ! [$WritableStreamDefaultControllerErrorIfNeeded$](|controller|,
      |enqueueResult|.\[[Value]]).
@@ -6095,7 +6124,7 @@ The following abstract operations support the implementaiton of the
  1. If ! [$ReadableStreamDefaultControllerCanCloseOrEnqueue$](|readableController|) is false, throw
     a {{TypeError}} exception.
  1. Let |enqueueResult| be [$ReadableStreamDefaultControllerEnqueue$](|readableController|,
-    |chunk|).
+    |chunk|, « »).
  1. If |enqueueResult| is an abrupt completion,
    1. Perform ! [$TransformStreamErrorWritableAndUnblockWrite$](|stream|,
       |enqueueResult|.\[[Value]]).
@@ -6626,13 +6655,16 @@ for="value-with-size">value</dfn> and <dfn for="value-with-size">size</dfn>.
 
 <div algorithm>
  <dfn abstract-op lt="EnqueueValueWithSize"
- id="enqueue-value-with-size">EnqueueValueWithSize(|container|, |value|, |size|)</dfn> performs the
+ id="enqueue-value-with-size">EnqueueValueWithSize(|container|, |value|, |size|, |transferList|)</dfn> performs the
  following steps:
 
  1. Assert: |container| has \[[queue]] and \[[queueTotalSize]] internal slots.
  1. If ! [$IsNonNegativeNumber$](|size|) is false, throw a {{RangeError}} exception.
  1. If |size| is +∞, throw a {{RangeError}} exception.
- 1. [=list/Append=] a new [=value-with-size=] with [=value-with-size/value=] |value| and
+ 1. Let |enqueuedValue| be |value|.
+ 1. If |container| has an \[[isOwning]] internal slot whose value is true, perform the following steps:
+    1. Set |enqueuedValue| to ? [$StructuredTransferOrClone$](|value|, |transferList|).
+ 1. [=list/Append=] a new [=value-with-size=] with [=value-with-size/value=] |enqueuedValue| and
     [=value-with-size/size=] |size| to |container|.\[[queue]].
  1. Set |container|.\[[queueTotalSize]] to |container|.\[[queueTotalSize]] + |size|.
 </div>
@@ -6652,6 +6684,10 @@ for="value-with-size">value</dfn> and <dfn for="value-with-size">size</dfn>.
  performs the following steps:
 
  1. Assert: |container| has \[[queue]] and \[[queueTotalSize]] internal slots.
+ 1. If |container| has an \[[isOwning]] internal slot whose value is true, perform the following steps until |container|.\[[queue]]
+    [=list/is empty=]:
+    1. Let |chunk| be ! [$DequeueValue$]([=this=]).
+    1. If |chunk| has [=dispose steps=], perform the [=dispose steps=] given |chunk|.
  1. Set |container|.\[[queue]] to a new empty [=list=].
  1. Set |container|.\[[queueTotalSize]] to 0.
 </div>
@@ -6711,7 +6747,7 @@ abstract operations are used to implement these "cross-realm transforms".
   1. Let |value| be ! [$Get$](|data|, "`value`").
   1. Assert: [$Type$](|type|) is String.
   1. If |type| is "`chunk`",
-   1. Perform ! [$ReadableStreamDefaultControllerEnqueue$](|controller|, |value|).
+   1. Perform ! [$ReadableStreamDefaultControllerEnqueue$](|controller|, |value|, « »).
   1. Otherwise, if |type| is "`close`",
     1. Perform ! [$ReadableStreamDefaultControllerClose$](|controller|).
     1. Disentangle |port|.
@@ -6860,6 +6896,14 @@ The following abstract operations are a grab-bag of utilities.
  1. Return ? [$StructuredDeserialize$](|serialized|, [=the current Realm=]).
 </div>
 
+<div algorithm>
+ <dfn abstract-op lt="StructuredTransferOrClone">StructuredTransferOrClone(|value|, |transferList|)</dfn>
+    performs the following steps:
+ 1. Let |serialized| be ? [$StructuredSerializeWithTransfer$](|value|, |transferList|).
+ 1. Let |deserialized| be ? [$StructuredDeserializeWithTransfer$](|serialized|, [=the current Realm=]).
+ 1. Return |deserialized|.\[[Deserialized]].
+</div>
+
 <h2 id="other-specs">Using streams in other specifications</h2>
 
 Much of this standard concerns itself with the internal machinery of streams. Other specifications
@@ -6992,13 +7036,14 @@ mark=] is greater than zero.
 </div>
 
 <div algorithm>
- To <dfn export for="ReadableStream">enqueue</dfn> the JavaScript value |chunk| into a
- {{ReadableStream}} |stream|:
+ To <dfn export for="ReadableStream">enqueue</dfn> the JavaScript value |chunk|
+ with an optional |transferList| into a {{ReadableStream}} |stream|:
 
  1. If |stream|.[=ReadableStream/[[controller]]=] [=implements=]
     {{ReadableStreamDefaultController}},
+  1. If |transferList| is null, set |transferList| to an [=list/is empty|empty=] list.
   1. Perform ! [$ReadableStreamDefaultControllerEnqueue$](|stream|.[=ReadableStream/[[controller]]=],
-     |chunk|).
+     |chunk|, |transferList|).
  1. Otherwise,
   1. Assert: |stream|.[=ReadableStream/[[controller]]=] [=implements=]
      {{ReadableByteStreamController}}.
diff --git a/reference-implementation/lib/ReadableStream-impl.js b/reference-implementation/lib/ReadableStream-impl.js
index 5123c8c0d..286f0e28b 100644
--- a/reference-implementation/lib/ReadableStream-impl.js
+++ b/reference-implementation/lib/ReadableStream-impl.js
@@ -29,7 +29,7 @@ exports.implementation = class ReadableStreamImpl {
         this, underlyingSource, underlyingSourceDict, highWaterMark
       );
     } else {
-      assert(!('type' in underlyingSourceDict));
+      assert(!('type' in underlyingSourceDict) || underlyingSourceDict.type === 'owning');
       const sizeAlgorithm = ExtractSizeAlgorithm(strategy);
       const highWaterMark = ExtractHighWaterMark(strategy, 1);
       aos.SetUpReadableStreamDefaultControllerFromUnderlyingSource(
diff --git a/reference-implementation/lib/ReadableStreamDefaultController-impl.js b/reference-implementation/lib/ReadableStreamDefaultController-impl.js
index 5c7ec7033..8abc763d0 100644
--- a/reference-implementation/lib/ReadableStreamDefaultController-impl.js
+++ b/reference-implementation/lib/ReadableStreamDefaultController-impl.js
@@ -17,12 +17,16 @@ exports.implementation = class ReadableStreamDefaultControllerImpl {
     aos.ReadableStreamDefaultControllerClose(this);
   }
 
-  enqueue(chunk) {
+  enqueue(chunk, options) {
+    const transferList = options.transfer;
+    if (transferList.length && !this._isOwning) {
+      throw new TypeError('The stream is not an owning stream and cannot make use of options');
+    }
     if (aos.ReadableStreamDefaultControllerCanCloseOrEnqueue(this) === false) {
       throw new TypeError('The stream is not in a state that permits enqueue');
     }
 
-    return aos.ReadableStreamDefaultControllerEnqueue(this, chunk);
+    return aos.ReadableStreamDefaultControllerEnqueue(this, chunk, transferList);
   }
 
   error(e) {
diff --git a/reference-implementation/lib/ReadableStreamDefaultController.webidl b/reference-implementation/lib/ReadableStreamDefaultController.webidl
index aeea7249f..041c731c5 100644
--- a/reference-implementation/lib/ReadableStreamDefaultController.webidl
+++ b/reference-implementation/lib/ReadableStreamDefaultController.webidl
@@ -1,8 +1,12 @@
+dictionary StructuredSerializeOptions {
+  sequence<object> transfer = [];
+};
+
 [Exposed=(Window,Worker,Worklet)]
 interface ReadableStreamDefaultController {
   readonly attribute unrestricted double? desiredSize;
 
   undefined close();
-  undefined enqueue(optional any chunk);
+  undefined enqueue(optional any chunk, optional StructuredSerializeOptions options = {});
   undefined error(optional any e);
 };
diff --git a/reference-implementation/lib/UnderlyingSource.webidl b/reference-implementation/lib/UnderlyingSource.webidl
index 7a0047638..b8aa75b70 100644
--- a/reference-implementation/lib/UnderlyingSource.webidl
+++ b/reference-implementation/lib/UnderlyingSource.webidl
@@ -12,4 +12,4 @@ callback UnderlyingSourceStartCallback = any (ReadableStreamController controlle
 callback UnderlyingSourcePullCallback = Promise<undefined> (ReadableStreamController controller);
 callback UnderlyingSourceCancelCallback = Promise<undefined> (optional any reason);
 
-enum ReadableStreamType { "bytes" };
+enum ReadableStreamType { "bytes", "owning" };
diff --git a/reference-implementation/lib/abstract-ops/miscellaneous.js b/reference-implementation/lib/abstract-ops/miscellaneous.js
index 08589a740..ed55a5268 100644
--- a/reference-implementation/lib/abstract-ops/miscellaneous.js
+++ b/reference-implementation/lib/abstract-ops/miscellaneous.js
@@ -20,3 +20,7 @@ exports.CloneAsUint8Array = O => {
   const buffer = O.buffer.slice(O.byteOffset, O.byteOffset + O.byteLength);
   return new Uint8Array(buffer);
 };
+
+exports.StructuredTransferOrClone = (value, transferList) => {
+  return globalThis.structuredClone(value, { transfer: transferList });
+};
diff --git a/reference-implementation/lib/abstract-ops/queue-with-sizes.js b/reference-implementation/lib/abstract-ops/queue-with-sizes.js
index 22086caa5..ed2834374 100644
--- a/reference-implementation/lib/abstract-ops/queue-with-sizes.js
+++ b/reference-implementation/lib/abstract-ops/queue-with-sizes.js
@@ -1,6 +1,6 @@
 'use strict';
 const assert = require('assert');
-const { IsNonNegativeNumber } = require('./miscellaneous.js');
+const { IsNonNegativeNumber, StructuredTransferOrClone } = require('./miscellaneous.js');
 
 exports.DequeueValue = container => {
   assert('_queue' in container && '_queueTotalSize' in container);
@@ -15,7 +15,7 @@ exports.DequeueValue = container => {
   return pair.value;
 };
 
-exports.EnqueueValueWithSize = (container, value, size) => {
+exports.EnqueueValueWithSize = (container, value, size, transferList) => {
   assert('_queue' in container && '_queueTotalSize' in container);
 
   if (!IsNonNegativeNumber(size)) {
@@ -24,7 +24,9 @@ exports.EnqueueValueWithSize = (container, value, size) => {
   if (size === Infinity) {
     throw new RangeError('Size must be a finite, non-NaN, non-negative number.');
   }
-
+  if (container._isOwning) {
+    value = StructuredTransferOrClone(value, transferList);
+  }
   container._queue.push({ value, size });
   container._queueTotalSize += size;
 };
@@ -37,9 +39,23 @@ exports.PeekQueueValue = container => {
   return pair.value;
 };
 
+const disposeStepsSymbol = Symbol('dispose-steps');
+
 exports.ResetQueue = container => {
   assert('_queue' in container && '_queueTotalSize' in container);
 
+  if (container._isOwning) {
+    while (container._queue.length > 0) {
+      const value = exports.DequeueValue(container);
+      if (typeof value[disposeStepsSymbol] === 'function') {
+        try {
+          value[disposeStepsSymbol]();
+        } catch (closeException) {
+          // Nothing to do.
+        }
+      }
+    }
+  }
   container._queue = [];
   container._queueTotalSize = 0;
 };
diff --git a/reference-implementation/lib/abstract-ops/readable-streams.js b/reference-implementation/lib/abstract-ops/readable-streams.js
index 5cd4814b3..b40fd5a55 100644
--- a/reference-implementation/lib/abstract-ops/readable-streams.js
+++ b/reference-implementation/lib/abstract-ops/readable-streams.js
@@ -6,7 +6,7 @@ const { promiseResolvedWith, promiseRejectedWith, newPromise, resolvePromise, re
   require('../helpers/webidl.js');
 const { CanTransferArrayBuffer, Call, CopyDataBlockBytes, CreateArrayFromList, GetIterator, GetMethod, IsDetachedBuffer,
         IteratorComplete, IteratorNext, IteratorValue, TransferArrayBuffer, typeIsObject } = require('./ecmascript.js');
-const { CloneAsUint8Array, IsNonNegativeNumber } = require('./miscellaneous.js');
+const { CloneAsUint8Array, IsNonNegativeNumber, StructuredTransferOrClone } = require('./miscellaneous.js');
 const { EnqueueValueWithSize, ResetQueue } = require('./queue-with-sizes.js');
 const { AcquireWritableStreamDefaultWriter, IsWritableStreamLocked, WritableStreamAbort,
         WritableStreamDefaultWriterCloseWithErrorPropagation, WritableStreamDefaultWriterRelease,
@@ -90,7 +90,7 @@ function CreateReadableStream(startAlgorithm, pullAlgorithm, cancelAlgorithm, hi
 
   const controller = ReadableStreamDefaultController.new(globalThis);
   SetUpReadableStreamDefaultController(
-    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm
+    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm, false
   );
 
   return stream;
@@ -341,7 +341,7 @@ function ReadableStreamTee(stream, cloneForBranch2) {
   if (ReadableByteStreamController.isImpl(stream._controller)) {
     return ReadableByteStreamTee(stream);
   }
-  return ReadableStreamDefaultTee(stream, cloneForBranch2);
+  return ReadableStreamDefaultTee(stream, stream._controller._isOwning ? true : cloneForBranch2);
 }
 
 function ReadableStreamDefaultTee(stream, cloneForBranch2) {
@@ -393,10 +393,10 @@ function ReadableStreamDefaultTee(stream, cloneForBranch2) {
           // }
 
           if (canceled1 === false) {
-            ReadableStreamDefaultControllerEnqueue(branch1._controller, chunk1);
+            ReadableStreamDefaultControllerEnqueue(branch1._controller, chunk1, []);
           }
           if (canceled2 === false) {
-            ReadableStreamDefaultControllerEnqueue(branch2._controller, chunk2);
+            ReadableStreamDefaultControllerEnqueue(branch2._controller, chunk2, []);
           }
 
           reading = false;
@@ -1075,7 +1075,7 @@ function ReadableStreamDefaultControllerClose(controller) {
   }
 }
 
-function ReadableStreamDefaultControllerEnqueue(controller, chunk) {
+function ReadableStreamDefaultControllerEnqueue(controller, chunk, transferList) {
   if (ReadableStreamDefaultControllerCanCloseOrEnqueue(controller) === false) {
     return;
   }
@@ -1083,6 +1083,14 @@ function ReadableStreamDefaultControllerEnqueue(controller, chunk) {
   const stream = controller._stream;
 
   if (IsReadableStreamLocked(stream) === true && ReadableStreamGetNumReadRequests(stream) > 0) {
+    if (controller._isOwning) {
+      try {
+        chunk = StructuredTransferOrClone(chunk, transferList);
+      } catch (chunkCloneError) {
+        ReadableStreamDefaultControllerError(controller, chunkCloneError);
+        throw chunkCloneError;
+      }
+    }
     ReadableStreamFulfillReadRequest(stream, chunk, false);
   } else {
     let chunkSize;
@@ -1094,7 +1102,7 @@ function ReadableStreamDefaultControllerEnqueue(controller, chunk) {
     }
 
     try {
-      EnqueueValueWithSize(controller, chunk, chunkSize);
+      EnqueueValueWithSize(controller, chunk, chunkSize, transferList);
     } catch (enqueueE) {
       ReadableStreamDefaultControllerError(controller, enqueueE);
       throw enqueueE;
@@ -1149,7 +1157,7 @@ function ReadableStreamDefaultControllerCanCloseOrEnqueue(controller) {
 }
 
 function SetUpReadableStreamDefaultController(
-  stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm) {
+  stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm, isOwning) {
   assert(stream._controller === undefined);
 
   controller._stream = stream;
@@ -1170,6 +1178,8 @@ function SetUpReadableStreamDefaultController(
   controller._pullAlgorithm = pullAlgorithm;
   controller._cancelAlgorithm = cancelAlgorithm;
 
+  controller._isOwning = isOwning;
+
   stream._controller = controller;
 
   const startResult = startAlgorithm();
@@ -1196,7 +1206,7 @@ function SetUpReadableStreamDefaultControllerFromUnderlyingSource(
   let startAlgorithm = () => undefined;
   let pullAlgorithm = () => promiseResolvedWith(undefined);
   let cancelAlgorithm = () => promiseResolvedWith(undefined);
-
+  const isOwning = underlyingSourceDict.type === 'owning';
   if ('start' in underlyingSourceDict) {
     startAlgorithm = () => underlyingSourceDict.start.call(underlyingSource, controller);
   }
@@ -1208,8 +1218,8 @@ function SetUpReadableStreamDefaultControllerFromUnderlyingSource(
   }
 
   SetUpReadableStreamDefaultController(
-    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm
-  );
+    stream, controller, startAlgorithm, pullAlgorithm, cancelAlgorithm, highWaterMark, sizeAlgorithm,
+    isOwning);
 }
 
 // Byte stream controllers
@@ -1911,7 +1921,7 @@ function ReadableStreamFromIterable(asyncIterable) {
         ReadableStreamDefaultControllerClose(stream._controller);
       } else {
         const value = IteratorValue(iterResult);
-        ReadableStreamDefaultControllerEnqueue(stream._controller, value);
+        ReadableStreamDefaultControllerEnqueue(stream._controller, value, []);
       }
     });
   }
diff --git a/reference-implementation/lib/abstract-ops/transform-streams.js b/reference-implementation/lib/abstract-ops/transform-streams.js
index 4edc5f10b..d78fdbc45 100644
--- a/reference-implementation/lib/abstract-ops/transform-streams.js
+++ b/reference-implementation/lib/abstract-ops/transform-streams.js
@@ -165,7 +165,7 @@ function TransformStreamDefaultControllerEnqueue(controller, chunk) {
   // accept TransformStreamDefaultControllerEnqueue() calls.
 
   try {
-    ReadableStreamDefaultControllerEnqueue(readableController, chunk);
+    ReadableStreamDefaultControllerEnqueue(readableController, chunk, []);
   } catch (e) {
     // This happens when readableStrategy.size() throws.
     TransformStreamErrorWritableAndUnblockWrite(stream, e);
diff --git a/reference-implementation/lib/abstract-ops/writable-streams.js b/reference-implementation/lib/abstract-ops/writable-streams.js
index cf303bfe7..88eef0888 100644
--- a/reference-implementation/lib/abstract-ops/writable-streams.js
+++ b/reference-implementation/lib/abstract-ops/writable-streams.js
@@ -637,7 +637,7 @@ function WritableStreamDefaultControllerClearAlgorithms(controller) {
 }
 
 function WritableStreamDefaultControllerClose(controller) {
-  EnqueueValueWithSize(controller, closeSentinel, 0);
+  EnqueueValueWithSize(controller, closeSentinel, 0, undefined);
   WritableStreamDefaultControllerAdvanceQueueIfNeeded(controller);
 }
 
@@ -729,7 +729,7 @@ function WritableStreamDefaultControllerProcessWrite(controller, chunk) {
 
 function WritableStreamDefaultControllerWrite(controller, chunk, chunkSize) {
   try {
-    EnqueueValueWithSize(controller, chunk, chunkSize);
+    EnqueueValueWithSize(controller, chunk, chunkSize, undefined);
   } catch (enqueueE) {
     WritableStreamDefaultControllerErrorIfNeeded(controller, enqueueE);
     return;
diff --git a/reference-implementation/run-web-platform-tests.js b/reference-implementation/run-web-platform-tests.js
index 0f685159e..5cc9021af 100644
--- a/reference-implementation/run-web-platform-tests.js
+++ b/reference-implementation/run-web-platform-tests.js
@@ -39,7 +39,6 @@ async function main() {
     'readable-byte-streams/non-transferable-buffers.any.html',
     'readable-streams/owning-type-message-port.any.html', // disabled due to MessagePort use.
     'readable-streams/owning-type-video-frame.any.html', // disabled due to VideoFrame use.
-    'readable-streams/owning-type.any.html', // FIXME: reenable this test once owning type PR lands.
     'transferable/transform-stream-members.any.html' // FIXME: reenable if structuredClone is aligned.
   ];
   const anyTestPattern = /\.any\.html$/;
@@ -64,6 +63,7 @@ async function main() {
           }
         };
       };
+      window.structuredClone = globalThis.structuredClone;
       window.eval(bundledJS);
     },
     filter(testPath) {