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SpatialKey offers two powerful ways to evaluate concentration of risk: the Accumulations App and Underwriting Accumulation Analysis. Although both measure how exposures cluster geographically, they serve very different business purposes and operate on different datasets, models, and workflows.

This article explains the distinctions between the two so you know which tool to use for portfolio management versus underwriting a new submission.

Overview: Portfolio Management vs. Submission Evaluation

Feature	Accumulations App	Underwriting Accumulation Analysis
Primary purpose	Portfolio‑level exposure management	Evaluate impact of adding new risks during underwriting
Data analyzed	Full exposure datasets	Prospective submission schedule + (optional) portfolio
Models available	Ring, Grid, Target	Magic Ring, Target, or Shapes (ZIPs, Counties, States)
Decision focus	Identify and monitor highest concentrations across the book	Go/no‑go decisions based on underwriting guidelines
Visualization & reporting	Rich maps, ranking views, configurable models	Submission-focused maps, over/under thresholds, location-level reports
Who uses it	Portfolio managers, cat modelers, exposure management teams	Underwriters evaluating individual submissions

The Accumulations App

Portfolio-level, exploratory, and model‑driven

The Accumulations App is designed for exploring concentration patterns across your entire portfolio. It helps you discover where your riskiest clusters are by running configurable models over the full dataset.

What it’s used for

• Identifying peak exposure accumulation areas
• Running ring, grid, or target models to analyze patterns across millions of records
• Monitoring concentrations across time for portfolio health
• Supporting exposure management, reinsurance decisions, and portfolio optimization

How it works

1. Select a dataset
   Choose any portfolio dataset your organization has loaded into SpatialKey.
2. Choose an accumulation configuration
   Options include:
   • Ring model (overlapping rings with customizable radius & damage ratio)
   • Grid model (overlapping grids with adjustable size & damage ratio)
   • Target model (concentric rings around a reference dataset such as terror targets)
3. Select a metric and threshold
   Apply financial metrics (e.g., TIV) and minimum thresholds to filter results.
4. Run the analysis
   SpatialKey ranks your top accumulation zones so you can quickly identify areas where risk is concentrated.

Ideal for:

• Exposure managers looking at book‑wide risk
• Understanding catastrophe accumulations or terror target proximity
• Tracking how concentrations change over time
• Strategic portfolio planning and reporting

Underwriting Accumulations (Underwriting App)

Submission-focused, rules‑based, and decision‑oriented

The Underwriting Accumulation feature is built specifically for underwriting workflows. Rather than scanning the whole portfolio, it focuses on how a new submission affects your existing concentrations.

What it’s used for

• Evaluating whether adding a new risk will exceed your organization’s capacity thresholds
• Applying underwriting-specific rules such as:
  • Ring or shape models
  • Policy terms
  • Damage factors
  • Custom capacity thresholds
• Producing go/no-go bind decisions

Models available for underwriting

SpatialKey provides underwriting‑configured models such as:

Magic Ring

• Applies multiple overlapping rings around each schedule location
• Deduplicates rings and identifies the worst‑case exposure within radius
• Ideal for finding peak accumulations around prospective locations

Target Analysis

• Centers rings on the schedule location
• Totals exposure (schedule + portfolio) within radius

Shape‑based Models

• Uses geopolitical zones such as ZIP Codes, Counties, or States
• Ideal for regulatory or rule‑driven underwriting workflows
• Provides consistent, fast zone‑based accumulation checks

How financials are handled

The analysis uses:

• TIV or policy terms for new locations
• Portfolio policy terms, facultative reinsurance, and special conditions for existing risks
• Calculates ground-up, gross, and net where possible
• Falls back to best available data (e.g., TIV as proxy) if inputs are limited

What the underwriter sees

• A clear over/under capacity indicator for each schedule location
• Detailed exposure lists showing schedule vs. portfolio contributors
• Drill-down map views for each location
• Option to export results to CSV

Ideal for:

• Underwriters making bind decisions
• Quickly assessing whether a submission introduces problematic concentrations
• Running consistent, rule‑based checks aligned with your organization’s underwriting guidelines

When to Use Which?

Use the Accumulations App when you need to:

• Explore or monitor concentrations across your entire book
• Run optimized ring, grid, or target models for exposure management
• Identify and rank hotspots for portfolio decisions
• Produce visualizations and portfolio‑level reports

Use Underwriting Accumulations when you need to:

• Evaluate the impact of a single submission or schedule
• Apply organizational capacity rules and thresholds
• Perform fast, repeatable risk checks at bind time
• Enforce guidelines consistently across underwriting teams