
retention, which is particularly valuable in dealing
with high-net-worth individuals and corporate
banking.".
Since social network effects significantly
influence churn behavior, interventions supporting
referral chains and community structures are
deployed to prevent cascade churn. Upon the
presence of a hub client, as identified by degree
centrality more than 50, indicating churn intention,
preemptive loyalty rewards are given to their direct
referrals. This tactic prevents the transmission of
churn within the network and, as indicated in a six-
month controlled test (Bauer and Dietmar, 2021),
successfully avoids 62% of potential referral-based
attrition.
Second, community-based incentives are given to
client groups that are highly internally connected as
reflected in terms of having a modularity score that
exceeds 0.8. In such a situation, group retention
bonuses such as fee waivers or provision of special
lending rates to the entire group in the event of 80%
group members maintaining active accounts prevent
community disintegration and bulk outflows.
For the highly causal policy-sensitive customers,
dynamic pricing buffers are used to counter
macroeconomic impacts. Customers with a causal
policy impact score of over 0.6, are offered temporary
rate locks during central bank adjustment periods,
offering fiscal stability in the event of changing
economic conditions (Huang et al., 2023). The
intervention has been found to reduce policy-induced
churn by 29% in Q3 2023, demonstrating the worth
of adaptive financial product forms that serve to
dampen external shocks.
3.2.2 Limitations of the Current Framework
Though it provides advantages, the TGN model poses
four challenges that must be overcome to improve its
performance in real banking application.
The first issue concerns temporal sparsity of data,
as a portion of clients is defined by low transaction
frequency. Specifically, 23% of the data consist of
clients with fewer than five transactions per month,
which corresponds to 38% higher prediction variance
for this category. Sparse interaction histories make it
difficult to establish strong temporal dependencies,
which lowers the accuracy of churn risk estimation.
The second limitation involves causal inference
assumptions inherent in the doubly robust estimator.
The doubly robust estimator assumes no unmeasured
confounders, an assumption that can be violated in
cases where external market trends influence multiple
clients simultaneously. For instance, cryptocurrency
price volatility can trigger huge banking withdrawals,
but these trends are beyond the TGN's transactional
causal analysis.
Another key challenge is computational overhead.
In order to update the graph in real time, there must
be an average of 12 milliseconds' processing per
transaction, although this increases to 1.9 seconds of
latency for rush hours, especially when transaction
rates are more than 5,000 per minute. Through graph
pruning and event-based updates, this is alleviated
somewhat, but computational scaling is still a
problem for larger data sets.
Finally, privacy and ethical issues arise as a result
of social network analysis methods embedded within
TGN. Inferring sensitive connections from co-
occurrences of transactions—e.g., inferring close
family relations based on joint payment patterns—
would be in danger of violating GDPR Article 9, i.e.,
prohibited automated inference of protected features
without an overt user confirmation (Zhang et al.,
2023).
3.2.3 Future research Directions
In response to these challenges, three research
priorities are set, each designed to improve the TGN
framework to better its robustness, interpretability,
and alignment with privacy issues.
First, sparse temporal graph learning techniques
can be explored to enhance predictive accuracy for
low-activity clients. Self-supervised pretraining with
masked graph autoencoders (Mengqi et al., 2021) has
the potential to allow the model to learn from
incomplete transaction histories, improving
performance in sparse data environments. In addition,
meta-learning approaches such as Model-Agnostic
Meta-Learning (MAML) can be applied for better
adaptation of model parameters to new clients,
reducing cold-start biases.
Second, causal temporal graph networks need to
be built to control for confounding variables for
policy-based churn prediction. This can be achieved
using instrumental variable analysis (Hunag et al.,
2023), which separates unobserved confounders in
customer behavior. Counterfactual policy testing can
also be used in order to identify various
macroeconomic conditions, so that banks can test
"what-if" and effectively modify their financial
planning.
Finally, advancement in privacy-preserving
deployment will be critical to meet regulatory
demands. Homomorphic encryption can be employed
to enable secure computation over encrypted
transaction graphs, eliminating raw data sharing
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