diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index fa2903414f..5de8a8053f 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -36,14 +36,6 @@ import { from_async_derived, set_from_async_derived } from '../../reactivity/der
 import { raf } from '../../timing.js';
 import { loop } from '../../loop.js';
 
-/** @type {Boundary | null} */
-export let active_boundary = null;
-
-/** @param {Boundary | null} boundary */
-export function set_active_boundary(boundary) {
-	active_boundary = boundary;
-}
-
 /**
  * @typedef {{
  * 	 onerror?: (error: unknown, reset: () => void) => void;
@@ -107,9 +99,7 @@ export class Boundary {
 		this.#props = props;
 		this.#children = children;
 
-		this.parent = active_boundary;
-
-		active_boundary = this;
+		this.parent = /** @type {Effect} */ (active_effect).b;
 
 		this.#effect = block(() => {
 			var boundary_effect = /** @type {Effect} */ (active_effect);
@@ -245,8 +235,6 @@ export class Boundary {
 		if (hydrating) {
 			this.#anchor = hydrate_node;
 		}
-
-		active_boundary = this.parent;
 	}
 
 	has_pending_snippet() {
@@ -257,12 +245,10 @@ export class Boundary {
 	 * @param {() => Effect | null} fn
 	 */
 	#run(fn) {
-		var previous_boundary = active_boundary;
 		var previous_effect = active_effect;
 		var previous_reaction = active_reaction;
 		var previous_ctx = component_context;
 
-		active_boundary = this;
 		set_active_effect(this.#effect);
 		set_active_reaction(this.#effect);
 		set_component_context(this.#effect.ctx);
@@ -270,7 +256,6 @@ export class Boundary {
 		try {
 			return fn();
 		} finally {
-			active_boundary = previous_boundary;
 			set_active_effect(previous_effect);
 			set_active_reaction(previous_reaction);
 			set_component_context(previous_ctx);
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index e8b4feda99..ec97bb4828 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -39,7 +39,6 @@ import { queue_micro_task } from '../task.js';
 import { active_effect, get } from '../../runtime.js';
 import { DEV } from 'esm-env';
 import { derived_safe_equal } from '../../reactivity/deriveds.js';
-import { active_boundary } from './boundary.js';
 
 /**
  * The row of a keyed each block that is currently updating. We track this
@@ -139,7 +138,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 
 	var was_empty = false;
 
-	var boundary = active_boundary;
+	var boundary = /** @type {Effect} */ (active_effect).b;
 
 	/** @type {Map<any, EachItem>} */
 	var offscreen_items = new Map();
diff --git a/packages/svelte/src/internal/client/dom/blocks/if.js b/packages/svelte/src/internal/client/dom/blocks/if.js
index 2a6a52c446..d8ad6f273a 100644
--- a/packages/svelte/src/internal/client/dom/blocks/if.js
+++ b/packages/svelte/src/internal/client/dom/blocks/if.js
@@ -10,8 +10,8 @@ import {
 } from '../hydration.js';
 import { block, branch, pause_effect, resume_effect } from '../../reactivity/effects.js';
 import { HYDRATION_START_ELSE, UNINITIALIZED } from '../../../../constants.js';
-import { active_boundary } from './boundary.js';
 import { create_text, should_defer_append } from '../operations.js';
+import { active_effect } from '../../runtime.js';
 
 /**
  * @param {TemplateNode} node
@@ -50,7 +50,7 @@ export function if_block(node, fn, elseif = false) {
 	/** @type {Effect | null} */
 	var pending_effect = null;
 
-	var boundary = active_boundary;
+	var boundary = /** @type {Effect} */ (active_effect).b;
 
 	function commit() {
 		if (offscreen_fragment !== null) {
diff --git a/packages/svelte/src/internal/client/dom/blocks/key.js b/packages/svelte/src/internal/client/dom/blocks/key.js
index 4c6cce7d79..2c7e0b4cd6 100644
--- a/packages/svelte/src/internal/client/dom/blocks/key.js
+++ b/packages/svelte/src/internal/client/dom/blocks/key.js
@@ -4,8 +4,8 @@ import { block, branch, pause_effect } from '../../reactivity/effects.js';
 import { not_equal, safe_not_equal } from '../../reactivity/equality.js';
 import { is_runes } from '../../context.js';
 import { hydrate_next, hydrate_node, hydrating } from '../hydration.js';
-import { active_boundary } from './boundary.js';
 import { create_text, should_defer_append } from '../operations.js';
+import { active_effect } from '../../runtime.js';
 
 /**
  * @template V
@@ -33,7 +33,7 @@ export function key_block(node, get_key, render_fn) {
 	/** @type {DocumentFragment | null} */
 	var offscreen_fragment = null;
 
-	var boundary = active_boundary;
+	var boundary = /** @type {Effect} */ (active_effect).b;
 
 	var changed = is_runes() ? not_equal : safe_not_equal;
 
diff --git a/packages/svelte/src/internal/client/dom/blocks/svelte-component.js b/packages/svelte/src/internal/client/dom/blocks/svelte-component.js
index 330150a80c..9311fab62a 100644
--- a/packages/svelte/src/internal/client/dom/blocks/svelte-component.js
+++ b/packages/svelte/src/internal/client/dom/blocks/svelte-component.js
@@ -1,9 +1,9 @@
 /** @import { TemplateNode, Dom, Effect } from '#client' */
 import { EFFECT_TRANSPARENT } from '../../constants.js';
 import { block, branch, pause_effect } from '../../reactivity/effects.js';
+import { active_effect } from '../../runtime.js';
 import { hydrate_next, hydrate_node, hydrating } from '../hydration.js';
 import { create_text, should_defer_append } from '../operations.js';
-import { active_boundary } from './boundary.js';
 
 /**
  * @template P
@@ -32,7 +32,7 @@ export function component(node, get_component, render_fn) {
 	/** @type {Effect | null} */
 	var pending_effect = null;
 
-	var boundary = active_boundary;
+	var boundary = /** @type {Effect} */ (active_effect).b;
 
 	function commit() {
 		if (effect) {
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index c54f39a774..554b3bce27 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -14,7 +14,6 @@ import {
 	set_is_flushing_effect,
 	set_signal_status,
 	untrack,
-	skip_reaction,
 	untracking
 } from '../runtime.js';
 import {
@@ -34,8 +33,7 @@ import {
 	INSPECT_EFFECT,
 	HEAD_EFFECT,
 	MAYBE_DIRTY,
-	EFFECT_PRESERVED,
-	BOUNDARY_EFFECT
+	EFFECT_PRESERVED
 } from '../constants.js';
 import { set } from './sources.js';
 import * as e from '../errors.js';
@@ -43,7 +41,7 @@ import { DEV } from 'esm-env';
 import { define_property } from '../../shared/utils.js';
 import { get_next_sibling } from '../dom/operations.js';
 import { async_derived, derived } from './deriveds.js';
-import { active_boundary, capture, suspend } from '../dom/blocks/boundary.js';
+import { capture, suspend } from '../dom/blocks/boundary.js';
 import { component_context, dev_current_component_function } from '../context.js';
 
 /**