Before you merge anything, you want to know one thing: what's going to survive?
It's the right question. A merge in HubSpot is permanent. There is no undo button. Once you confirm it, the secondary record is gone. And if you didn't understand what the merge would do to your properties, your timeline, your workflows, and your integrations, you might not like what you're left with.
This article covers exactly what happens to your data across every dimension: property values, activity history, associations, lists, workflows, and more. It also covers the places where HubSpot's default behaviour might surprise you, and how to merge confidently at scale without losing data you need.
| Data type | What happens after merge |
|---|---|
| Property values | Primary record wins; secondary fills empty fields only |
| Activity history | Combined from both records |
| Associations | Combined from both records |
| Static list memberships | Combined from both records |
| Active list memberships | Re-evaluated against the merged record's current properties |
| Workflow enrollments | Both records unenrolled |
| Sequence enrollments |
Retained on the surviving record |
Every HubSpot merge involves two records: a primary and a secondary. Choosing the right primary record is probably the most consequential decision in a merge. Get it wrong and you may preserve the wrong property values, lose a timeline, or disrupt an active deal.
The default rule in HubSpot: the primary record's property values win. If the primary has a value for a field, that's what you'll see after the merge, even if the secondary had something more accurate or more recent. The one exception is empty fields. If the primary has no value for a property, HubSpot will pull through the secondary's value automatically.
This is easy to manage for a single merge. It becomes harder when you're running thousands.
When you merge two records, HubSpot applies this hierarchy:
Primary record's values take precedence. Wherever the primary has a value, it wins. The secondary's value for that property is discarded.
Secondary fills in the blanks. If the primary has no value for a field (null or empty), HubSpot carries the secondary's value across to the merged record.
You can override the defaults. During a manual merge, HubSpot shows you both records' values side by side and lets you choose which to keep, property by property. This is useful for one-off merges where you need precise control, but it doesn't scale when you're working through a backlog of thousands. Koalify's merge rules let you define that logic once and apply it automatically across every merge.
A few important edge cases to know:
Create date always takes the oldest value, regardless of which record is primary. The merged record will show the earliest "first seen" date across both records, which is generally what you want.
Record ID changes. The merged record gets a new Record ID. The original IDs from both records aren't deleted. They're stored in the Merged Contact IDs (or equivalent) property, which you can use to trace history and run filtered views.
Property timestamps reset to the date of the merge. If a merge updates a property value, the "last modified" date will show when the merge happened, not when the property was originally set. For audit-heavy or compliance-driven teams, this is worth knowing.
Several contact properties don't follow the primary-wins rule:
Email address. The primary contact's email is kept as the primary address. The secondary contact's email is added as a secondary email address rather than discarded. This matters for deliverability and for identifying previously merged records.
Lifecycle stage. HubSpot keeps whichever stage is furthest down the funnel. If one contact is a Lead and the other is a Customer, the merged contact will be a Customer. You won't accidentally downgrade a contact's lifecycle stage by merging.
Number of conversions and unique forms submitted. These are added together. If the primary contact submitted three forms and the secondary submitted two, the merged contact will show five. The full conversion history is preserved.
Marketing contact status. HubSpot keeps the most marketable status. If one contact is set as Marketing and the other as Non-marketing, the merged contact will be set as Marketing.
Analytics properties. Page views and session data are re-synced and combined across both contacts, so you see the total engagement from both records.
Original Traffic Source. The oldest value is kept, unless the source was manually updated. If it was, the manually set value takes precedence.
Legal basis. The most recent values from both contact records are kept. This is particularly important for GDPR-compliant portals. You won't lose consent data from either record.
Company merges have their own set of exceptions to the default logic:
Company domain name. The primary company's domain is maintained as the primary domain. The secondary company's domain is added as a secondary domain name rather than deleted. If the primary company has no domain prior to the merge, the secondary's domain becomes the primary.
Lifecycle stage. Same logic as contacts: the stage furthest down the funnel is kept. A company marked as Customer won't be overwritten by a duplicate marked as Lead.
Analytics properties. Page views and visits are re-synced and combined across both company records.
Original Traffic Source. The oldest value is kept, unless the source was manually updated, in which case the manual value remains.
This is one of the better behaviours in HubSpot's merge logic: all activities from both records are combined onto the merged record. Emails, calls, meetings, notes, form submissions, page views. The full timeline from the secondary record carries across.
In practice, a merged contact retains the complete engagement history from both versions of that record. You won't lose the original demo booking because it lived on the secondary. You won't lose the email thread because the sales rep used a different record.
The timeline consolidation is usually the outcome buyers are most relieved about. When you have 2,800 duplicate deals scattering your pipeline data across records, the ability to merge and consolidate the activity history is what makes the data usable again.
HubSpot also logs a merge activity on the surviving record, so you have a clear audit trail of when the merge happened and which records were involved.
All associations from both records carry across to the merged record. If the secondary contact was associated with three companies and the primary was associated with two, the merged contact will be associated with all five.
One nuance for company associations: HubSpot allows one company to be set as the Primary association for a contact. After a merge, the primary record's primary company association takes precedence. If you want a different company to hold that label, you'll need to update it manually after the merge.
For deal and ticket associations, everything carries across. Both records' deals and tickets will appear on the merged contact or company. No deal history lost, no ticket orphaned.
There is one limit to be aware of: HubSpot caps the number of associations a single record can hold. If combining the associations from both records would exceed that limit, the merge will fail with an association limit error. This is uncommon for most portals, but it does come up in large or complex instances where a single company record has been associated with hundreds of contacts, deals, or tickets over time. If you hit this error, you'll need to remove some existing associations from the primary record before the merge can complete.
Static segments and active segments behave differently after a merge.
Static segments. When two records are merged, both records' static segment memberships are retained on the surviving record. The merged record will be a member of every static segment that either the primary or secondary record belonged to before the merge.
Active segments. Active segment membership is re-evaluated based on the merged record's current properties. If the surviving record meets the segment criteria, it stays. If the merge changed a property that was driving membership (for example, lifecycle stage or lead source), the record may drop out of segments you expected it to remain in.
The practical implication for anyone merging at scale: static segment memberships are safe, but it's worth auditing active segment criteria against the property values your merge rules will produce, as those outcomes are not guaranteed.
Merging a record can affect active workflow enrolments in ways that catch people off guard.
When two records are merged, both the primary and secondary records are deleted and a new record is created. This means any active workflow enrolments on either record are cancelled, as the original records no longer exist. The merged record starts fresh with no inherited enrolments. If a contact was mid-nurture or mid-campaign, you will need to manually re-enrol the surviving record if the workflow should continue.
There are two ways Koalify helps protect against this. First, you can configure duplicate rules to exclude records that are actively enrolled in a workflow from being flagged as duplicates, preventing them from being merged in the first place. Second, Koalify's record-preserving merge method keeps the primary record intact rather than creating a new one, which means the primary record's workflow enrolments are not interrupted.
When merging contacts that are enrolled in a sequence, the sequence enrolment is retained on the surviving record. The merge does not interrupt or cancel an active sequence, so there is no need to unenrol before merging or re-enrol manually afterwards.
HubSpot merges are permanent. There is no native unmerge function.
What you can do after a merge:
View merge history. The Merged Record IDs property on every merged record stores the original Record IDs of both records. You can use this to identify what was merged and when.
Export merge history. For merges performed via HubSpot's Data Quality tool, you can export the pre-merge property values for up to 90 days back. This gives you a reference point if something went wrong.
Recreate from secondary email addresses. For contacts, HubSpot stores the secondary email after a merge. You can create a new contact from that email if you ever need to split the records.
What you can't do: automatically restore all the property values, associations, and activity history to two separate records as they existed before the merge. This is why it's worth taking a backup before any bulk merge operation.
One-off merges through HubSpot's UI are manageable. You can review both records, choose your property values, and confirm. The risk is low because you're in control of each decision.
The challenge is when you have a backlog of hundreds or thousands of duplicates. At that point, you're not reviewing every merge individually. You need rules that make the right decisions automatically: which record should be primary, what logic determines that, how to protect records that are in active workflows.
This is exactly what Koalify's merge rules are built for. You define the logic once (which property determines the primary record, how to handle ties, which objects to include) and Koalify applies it consistently across every merge, whether you're running a bulk cleanup of 50,000 records or letting automation handle new duplicates as they arrive.
If you're about to start merging at scale and want to understand what to set up before you begin, our guide to bulk merging in HubSpot covers the full process. And if you want to make sure you can recover if anything goes wrong, taking a HubSpot backup first is always worth the time.
Can I undo a merge in HubSpot?
No. Once two records are merged, the secondary record is permanently deleted. HubSpot stores the original Record IDs in the Merged Record IDs property, and you can export pre-merge property values for merges done via the Data Quality tool (up to 90 days back). But there is no native unmerge function. This is why reviewing your merge rules and taking a backup before any bulk operation matters.
Which property values are kept after a HubSpot merge?
By default, the primary record's property values take precedence. If the primary has a value for a field, it wins. If the primary's field is empty, HubSpot carries across the secondary's value. For manual merges, you can override this by selecting which values to keep property by property. One exception: Create Date always reflects the oldest value from either record, regardless of which is primary.
What happens to segment memberships after a merge? Static segment memberships from both records are retained on the surviving record after a merge. Active segment memberships are re-evaluated based on the merged record's current properties: if the merged record still meets the segment criteria it stays, if not it falls out.
What happens to workflow enrolments when you merge records?
When two records are merged, both are unenrolled from any active workflows, as the original records no longer exist and a new record is created. The merged record starts fresh with no inherited enrolments. If a contact was mid-nurture or mid-campaign, you will need to manually re-enrol the surviving record if the workflow should continue.
Does merging HubSpot records affect Salesforce sync?
Yes. HubSpot's standard merge UI is disabled for contacts and companies that are actively synced with Salesforce. Merging Salesforce-synced records incorrectly can break the sync and orphan records on the Salesforce side. Koalify's hybrid merge handles Salesforce-connected portals specifically: it preserves the Salesforce Record ID on the surviving record and maintains sync integrity.
What happens to activity history after a merge?
All activity history from both records (emails, calls, meetings, notes, form submissions) is combined onto the merged record. You don't lose the timeline from the secondary record. The activity consolidation is complete, even if the property values from the secondary are overwritten.
Ready to start merging without the guesswork? Install Koalify free and see every duplicate flagged in your HubSpot, with the merge rules, primary/secondary logic, and Salesforce handling already built in.