diff --git a/reference/apm/cloud/apm-settings.md b/reference/apm/cloud/apm-settings.md
index 07d9b52e6..59039d3f2 100644
--- a/reference/apm/cloud/apm-settings.md
+++ b/reference/apm/cloud/apm-settings.md
@@ -53,6 +53,10 @@ If a setting is not supported by {{ech}}, you will get an error message when you
 Some settings that could break your cluster if set incorrectly are blocklisted. The following settings are generally safe in cloud environments. For detailed information about APM settings, check the [APM documentation](/solutions/observability/apm/configure-apm-server.md).
 ::::
 
+### Version 8.19+ and 9.1+ [ec_version_8_19_and_9_1]
+
+`apm-server.sampling.tail.ttl`
+:   Time-to-live (TTL) for trace events stored in the local storage of the APM Server during tail-based sampling. This TTL determines how long trace events are retained in the local storage while waiting for a sampling decision to be made. A greater TTL value increases storage space requirements. Should be at least 2 * Interval.
 
 ### Version 8.0+ [ec_version_8_0_3]
 
diff --git a/solutions/observability/apm/configure-apm-server.md b/solutions/observability/apm/configure-apm-server.md
index 6e6eb24bc..d1e3de773 100644
--- a/solutions/observability/apm/configure-apm-server.md
+++ b/solutions/observability/apm/configure-apm-server.md
@@ -77,6 +77,11 @@ If a setting is not supported on {{ecloud}}, you will get an error message when
 Some settings that could break your cluster if set incorrectly are blocklisted. The following settings are generally safe in cloud environments. For detailed information about APM settings, check the [APM documentation](/solutions/observability/apm/configure-apm-server.md).
 ::::
 
+### Version 8.19+ and 9.1+ [ec_version_8_19_and_9_1]
+
+`apm-server.sampling.tail.ttl`
+:   Time-to-live (TTL) for trace events stored in the local storage of the APM Server during tail-based sampling. This TTL determines how long trace events are retained in the local storage while waiting for a sampling decision to be made. A greater TTL value increases storage space requirements. Should be at least 2 * Interval.
+
 ### Version 8.0+ [ec_version_8_0_3]
 
 This stack version removes support for some previously supported settings. These are all of the supported settings for this version:
diff --git a/solutions/observability/apm/tail-based-sampling.md b/solutions/observability/apm/tail-based-sampling.md
index 7a27c3697..0658bdc19 100644
--- a/solutions/observability/apm/tail-based-sampling.md
+++ b/solutions/observability/apm/tail-based-sampling.md
@@ -74,6 +74,18 @@ Synchronization interval for multiple APM Servers. Should be in the order of ten
 | APM Server binary | `sampling.tail.interval` |
 | Fleet-managed | `Interval` |
 
+### TTL [sampling-tail-ttl-ref]
+
+Time-to-live (TTL) for trace events stored in the local storage of the APM Server during tail-based sampling. This TTL determines how long trace events are retained in the local storage while waiting for a sampling decision to be made. A greater TTL value increases storage space requirements. Should be at least 2 * Interval.
+
+Default: `30m` (30 minutes). (duration)
+
+|     |     |
+| --- | --- |
+| APM Server binary | `sampling.tail.ttl` |
+| Fleet-managed (version 9.1+) | `TTL` |
+
+
 ### Policies [sampling-tail-policies-ref]
 
 Criteria used to match a root transaction to a sample rate.