diff --git a/site/content/3.12/develop/http-api/indexes/multi-dimensional.md b/site/content/3.12/develop/http-api/indexes/multi-dimensional.md
index 5627af291b..fdef8245bd 100644
--- a/site/content/3.12/develop/http-api/indexes/multi-dimensional.md
+++ b/site/content/3.12/develop/http-api/indexes/multi-dimensional.md
@@ -128,8 +128,7 @@ paths:
                     competing indexes in AQL queries when there are multiple candidate indexes to
                     choose from.
 
-                    The `estimates` attribute is optional and defaults to `true` if not set.
-                    It has no effect on indexes other than `persistent`, `mdi`, and `mdi-prefixed`.
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
                     It cannot be disabled for non-unique `mdi` indexes because they have a fixed
                     selectivity estimate of `1`.
                   type: boolean
diff --git a/site/content/3.12/develop/http-api/indexes/persistent.md b/site/content/3.12/develop/http-api/indexes/persistent.md
index cb916d7aed..f147b16691 100644
--- a/site/content/3.12/develop/http-api/indexes/persistent.md
+++ b/site/content/3.12/develop/http-api/indexes/persistent.md
@@ -139,7 +139,7 @@ paths:
                     competing indexes in AQL queries when there are multiple candidate indexes to
                     choose from.
 
-                    The option has no effect on indexes other than `persistent`, `mdi`, and `mdi-prefixed`.
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
                   type: boolean
                   default: true
                 cacheEnabled:
diff --git a/site/content/3.12/develop/http-api/indexes/ttl.md b/site/content/3.12/develop/http-api/indexes/ttl.md
index 11fb88d96a..054bdcade5 100644
--- a/site/content/3.12/develop/http-api/indexes/ttl.md
+++ b/site/content/3.12/develop/http-api/indexes/ttl.md
@@ -59,6 +59,20 @@ paths:
                   maxItems: 1
                   items:
                     type: string
+                estimates:
+                  description: |
+                    This attribute controls whether index selectivity estimates are maintained for the
+                    index. Not maintaining index selectivity estimates can have a slightly positive
+                    impact on write performance.
+
+                    The downside of turning off index selectivity estimates is that
+                    the query optimizer is not able to determine the usefulness of different
+                    competing indexes in AQL queries when there are multiple candidate indexes to
+                    choose from.
+
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
+                  type: boolean
+                  default: true
                 expireAfter:
                   description: |
                     The time interval (in seconds) from the point in time stored in the `fields`
diff --git a/site/content/3.12/index-and-search/indexing/index-utilization.md b/site/content/3.12/index-and-search/indexing/index-utilization.md
index 46a4592bb0..6441050cda 100644
--- a/site/content/3.12/index-and-search/indexing/index-utilization.md
+++ b/site/content/3.12/index-and-search/indexing/index-utilization.md
@@ -20,7 +20,7 @@ to an index, an index can become more selective and thus reduce the number of do
 queries need to process.
 
 ArangoDB's `primary` and `edge` indexes automatically provide selectivity estimates.
-The `persistent`, `mdi`, and `mdi-prefixed` indexes do too, by default.
+The `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes do too, by default.
 Index selectivity estimates are provided in the web interface, the `indexes()` return 
 value and in the `explain()` output for a given query. 
 
diff --git a/site/content/3.13/develop/http-api/indexes/multi-dimensional.md b/site/content/3.13/develop/http-api/indexes/multi-dimensional.md
index 5627af291b..fdef8245bd 100644
--- a/site/content/3.13/develop/http-api/indexes/multi-dimensional.md
+++ b/site/content/3.13/develop/http-api/indexes/multi-dimensional.md
@@ -128,8 +128,7 @@ paths:
                     competing indexes in AQL queries when there are multiple candidate indexes to
                     choose from.
 
-                    The `estimates` attribute is optional and defaults to `true` if not set.
-                    It has no effect on indexes other than `persistent`, `mdi`, and `mdi-prefixed`.
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
                     It cannot be disabled for non-unique `mdi` indexes because they have a fixed
                     selectivity estimate of `1`.
                   type: boolean
diff --git a/site/content/3.13/develop/http-api/indexes/persistent.md b/site/content/3.13/develop/http-api/indexes/persistent.md
index cb916d7aed..f147b16691 100644
--- a/site/content/3.13/develop/http-api/indexes/persistent.md
+++ b/site/content/3.13/develop/http-api/indexes/persistent.md
@@ -139,7 +139,7 @@ paths:
                     competing indexes in AQL queries when there are multiple candidate indexes to
                     choose from.
 
-                    The option has no effect on indexes other than `persistent`, `mdi`, and `mdi-prefixed`.
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
                   type: boolean
                   default: true
                 cacheEnabled:
diff --git a/site/content/3.13/develop/http-api/indexes/ttl.md b/site/content/3.13/develop/http-api/indexes/ttl.md
index 11fb88d96a..054bdcade5 100644
--- a/site/content/3.13/develop/http-api/indexes/ttl.md
+++ b/site/content/3.13/develop/http-api/indexes/ttl.md
@@ -59,6 +59,20 @@ paths:
                   maxItems: 1
                   items:
                     type: string
+                estimates:
+                  description: |
+                    This attribute controls whether index selectivity estimates are maintained for the
+                    index. Not maintaining index selectivity estimates can have a slightly positive
+                    impact on write performance.
+
+                    The downside of turning off index selectivity estimates is that
+                    the query optimizer is not able to determine the usefulness of different
+                    competing indexes in AQL queries when there are multiple candidate indexes to
+                    choose from.
+
+                    The option has no effect on indexes other than `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes.
+                  type: boolean
+                  default: true
                 expireAfter:
                   description: |
                     The time interval (in seconds) from the point in time stored in the `fields`
diff --git a/site/content/3.13/index-and-search/indexing/index-utilization.md b/site/content/3.13/index-and-search/indexing/index-utilization.md
index 46a4592bb0..6441050cda 100644
--- a/site/content/3.13/index-and-search/indexing/index-utilization.md
+++ b/site/content/3.13/index-and-search/indexing/index-utilization.md
@@ -20,7 +20,7 @@ to an index, an index can become more selective and thus reduce the number of do
 queries need to process.
 
 ArangoDB's `primary` and `edge` indexes automatically provide selectivity estimates.
-The `persistent`, `mdi`, and `mdi-prefixed` indexes do too, by default.
+The `persistent`, `mdi`, `mdi-prefixed`, and `ttl` indexes do too, by default.
 Index selectivity estimates are provided in the web interface, the `indexes()` return 
 value and in the `explain()` output for a given query.