1. portfolio segmentation
Receivables’ portfolio is segmented on the basis of both
empirical judgement as well as statistical characteristics
estimated through statistical moments of default rates’ pattern.
Receivables from counterparties based in different countries
must be segmented separately as their default rates will be
correlated to the macro-economic parameters of their domiciled
countries.
Segments having similar range of statistical moments i.e. mean,
standard deviation, skewness and kurtosis are merged.
2. MEVS IDENTIFICATION
Historical data of maximum number of relevant macro-economic
variables is taken and tested for Correlation & Concordance with
portfolios’ historical default rates.
Macro-economic variables that qualify minimum thresholds of
correlation & concordance are taken for while other
non-qualifying variables are discarded.
Qualified macro-economic variables are further tested for
R-Square (Model Fit) and P-Values (Predictive Capability) for
default rates pattern through regressive analytics.
Macro-economic variables that qualify minimum thresholds of
model fit and predictive capability are taken while other
variables are statistically rejected.
Identified macro-economic variables are empirically back tested
to ascertain statistical validity.
This step is conducted for each segment of receivables’ default
rates as identified in portfolio segmentation process.
3. ECONOMIC SCENARIOS
Annual projected data for final MEVs is taken and YOY Intercepts
and Slopes of annual data points are estimated. Annual data
points are converted in quarterly data points through
Interpolation using estimated YOY intercepts and slopes and YOY
rate of changes is estimated for projected MEVs to Stationarize
data.
Stationarized MEVs projected data is combined with historical
standardized data points to create data stream. Factor Analysis
is conducted on data stream to estimate Eigenvalues &
Eigenvectors and Principal Components are identified using
Eigenvalues & Eigenvectors through Principal Component Analysis.
Primary Principal Component is identified on the basis of
Explained Cumulative Variance and Regressive Analytics are
conducted to test Statistical Fit & Predictive Accuracy of DRs
using Principal Components.
Base, Down and Up scenarios are identified by mapping movements
of DR with the increase in Principal Component using Visual
Cutoff Points on scree plot. Probabilistic weights are estimated
for each scenario as Realized Probabilities based on Cutoff
Points adjustments in historic default rate pattern.
Regressive Analytics are conducted to test Statistical Fit &
Predictive Accuracy of DRs under base, down and up scenarios
Slopes & Intercepts of base, down and up scenarios are used to
project DR changes under 3 scenarios (IFRS 9 requires minimum of
2 scenarios).
4. Pit pd simulations
The process of point in time probability of default requires
combining non-parametric approach with parametric approach under
IFRS 9 standard modeling.
Net Flow Rates are estimated from historical default rate
pattern under non-parametric approach and adjusted for its
standard deviation.
Economic overlay is created on historic net flow rates by
combining macro-economic scenarios through exponential
distribution which estimates point forward probabilities of
default under each scenario.
Final point in time probabilities of default for each segment of
receivables portfolio are estimated as weighted average of
scenario’s probabilistic weight and scenario driven probability
of default.
This is essentially a copula approach which substitutes
transition matrix which is extremely data intensive otherwise.
5. lgd simulations
PIT collateral values are estimated by extrapolating the
negative/positive Slope of valuation points over Euclidean Space
for collateralized exposures using estimated accelerators.
Segment-wise total outstanding exposure and total collateral
values are used to calculate Exposure Weighted LTVs for each
portfolio segment.
Historic Recovery Rates are used to estimate Mean Portfolio
Recovery Rates and Standard Deviation of Portfolio historic
recovery pattern.
Lower Bound of LGD Distribution is fixed at 0% and Upper Bound
is fixed at 100%.
Beta Distribution is used to estimate LGD for each segment with
collateral and Implied LGD Generator is used for clean
exposures.
6. Ead estimations
Total exposure under each portfolio segment is divided into 3
buckets as per IFRS 9 guidelines.
All gross exposure within each segment that is less than 30 days
past due (DPD) is summed under Bucket I together with any off
balance sheet exposure.
All gross exposure within each segment that is more than 30 days
past due but less than 89 days past due is summed under Bucket
II together with any exposure where risk has materially changed
since origination.
All net exposure within each segment that is more than 89 days
past due is summed under Bucket III. Net exposure is estimated
by reducing gross exposure to the extent of collaterization
after applying prudent haircuts.