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The Account Hierarchy lets CRM users quickly identify relevant contacts in the parent company and all of its divisions or subsidiaries based on their role. It enhances the functionality of vTiger by providing visibility and access to all the Account Subsidiary contacts directly from the Parent Account.

Now from the detail view of an Account, you can access the Account Hierarchy for that particular Account.The link to access the hierarchy is available through 'More Actions' > 'Show Account Hierarchy' (following is the snapshot to illustrate this)

Following snapshots illustrates how Account Hierarchy (The account name highlighted in black indicates the Account for which, the Account Hierarchy is shown) :-