BA006 · Correspondent Banking

Dormant Reactivation

Dormant reactivation is the behavioural-anomaly signal at the far end of the account lifecycle: an account that has sat idle -- sometimes for months, sometimes for years -- suddenly comes back to life with flows that dwarf anything it ever carried while active. The finding is not any single transaction on its own; a large deposit or a new counterparty can each look ordinary in isolation. What makes it a finding is the CONTRAST between the account's long silence and the size, shape and speed of what happens the moment it wakes up.

The signature lives in four places: how large the reactivating inflow is relative to what the account used to carry every month before it went quiet, how long the account sat dormant before that inflow landed (a longer silence makes the reactivation more anomalous, not less -- a bank would ordinarily expect a truly dormant account to be closed, not reawakened at scale), how much the account's behaviour after reactivation deviates from its prior profile (new counterparties and geographies it never dealt with before), and how quickly the reactivating funds drain back out again -- a wake-up-and-drain pattern is a far stronger signal than a wake-up-and-settle one.

Risk indicators

Reactivation Spike

• A reactivating inflow many multiples of the account's pre-dormancy average monthly
• No gradual ramp-up -- the account jumps straight to elevated activity

Dormancy Length

• Extended idle periods, often exceeding a year, before the reactivating inflow lands
• No account-closure or re-KYC event during the dormant period

Profile Deviation

• New counterparties appearing immediately after reactivation with no prior relationship
• New geographies inconsistent with the account's established footprint

Immediate Outflow

• Outbound amounts tracking the reactivating inflow almost 1:1
• Round-number consistency between the reactivating inflow and the outbound leg

Investigation actions

1. Resolve the account, its pre-dormancy counterparty, and every reactivation
2. Compute the reactivation spike ratio (reactivation amount / pre-dormancy average
3. Compute the dormancy length in days between the account's last activity and the
4. Count the new counterparties/geographies appearing after reactivation that were not
5. Compute the immediate outflow ratio (outflow amount / reactivation amount).
6. Score each of the four components against its band cut-lines.
7. Aggregate the weighted exposure score; escalate at or above the threshold.

Detection logic

1. Resolve the account, its pre-dormancy counterparty, and every reactivation counterparty (first, second). 2. Compute the reactivation spike ratio (reactivation amount / pre-dormancy average monthly activity). 3. Compute the dormancy length in days between the account's last activity and the reactivating inflow. 4. Count the new counterparties/geographies appearing after reactivation that were not part of the prior profile. 5. Compute the immediate outflow ratio (outflow amount / reactivation amount). 6. Score each of the four components against its band cut-lines. 7. Aggregate the weighted exposure score; escalate at or above the threshold.

Related typologies

Curated from fc-06-correspondent-banking-analytics-toolkit/typologies/BA006_Dormant_Reactivation.md