tower

EvidenceCanvasSeries

A reinsurance program as stacked layers, each written as its limit in excess of its attachment and split across the reinsurers who took a share of it.

Open in Playground

Use for a reinsurance or insurance tower — a catastrophe program, a casualty excess tower, a D&O program. The retention sits at the bottom, each layer above it is labeled in the market's notation ($40M xs $50M), and each layer is split into its reinsurers' shares, one color per reinsurer across every layer, with any unplaced share shown as Open.

riskownershipproportionboard-deck

When to use

The structure is the decision. A tower earns its slide when the conversation is about the program's shape — where the retention sits, how the layers stack, which reinsurers carry which part. For the cost of each layer, use stacked-bar or bar; for how losses would hit it, use waterfall.
Two to six layers. Every layer is the same height, so the bands thin as layers are added. Past six, merge the thin top layers or split the program across two slides.
Up to six reinsurers. Each reinsurer keeps one color across every layer. A seventh and beyond fold into one Others color, summed per layer, so name the ones the client will ask about.

When not to use

Reading the height as the size. The layers are drawn at equal height on purpose, so a $40M layer and a $200M layer look the same size. When the audience needs to SEE the size difference, show the limits as a bar chart instead.
Shares that are dollars. A share is a percentage of its layer. Write the reinsurer's line as 30%, not $12M: a dollar figure reads as 12 million percent.

Common mistakes

Writing the layer as attachment then limit ($50M xs $40M for a $40M layer sitting at $50M). The market's order is LIMIT xs ATTACHMENT: $40M xs $50M is $40M of cover above $50M. The chart reads it that way, so the reversed form draws the wrong boundaries.

Authoring

<!-- _class: tower -->

## Who carries each layer of the program.

- Layer 2 `$100M xs $50M`
  - Reinsurer A `60%`
  - Reinsurer B `40%`
- Layer 1 `$40M xs $10M`
  - Reinsurer A `50%`
  - Reinsurer C `50%`
- Retention `$10M`

Slots

Slot	Selector	Required	Description
`title`	`h2`	yes	Slide heading — say what the structure means for the client ('A $50M retention saves $3.7M'), not 'Program structure'.
`layers`	`ul > li`	yes	One li per layer: the layer name, then a trailing inline-code size in the market's notation — `Layer 2 \`$70M xs $90M\` `(limit, then` xs`,` x/s `or` excess of`, then attachment). A size with no` xs` is the retention, the band from zero to that figure. Any order: the chart sorts by attachment, lowest at the bottom.
`shares`	`li > ul > li`	no	Optional nested bullets under a layer, one per reinsurer: `Acme Re \`30%\``. Each reinsurer keeps one color across every layer. Shares that add up to less than 100% leave the rest as an` Open` segment; a layer with no shares is drawn plain.

Data shape

A layer's size reads like every chart number (lib/core/chart-values.js), on both sides of xs: $40M, USD 40mn, EUR 40 Mio. and 40,000,000 all mean the same.
Shares are percentages of the layer. Under 100% leaves an Open segment; over 100% is drawn scaled to the layer and the description says it is over-placed.

Anatomy

┌─────────────────────────────────────────┐
│  header                                 │
│        Where the pipeline leaks.        │
│                                         │
│   Visitors    [============]   12,000   │
│     62%        [========]      4,800    │
│   Activated    [=====]         2,160    │
│     40%        [==]              864    │
│   Paid         [=]               670    │
│                                         │
│  footer                           1/19  │
└─────────────────────────────────────────┘

stacked-barthe premium or cost of each layer, compared on a scale
waterfallhow a loss or a result walks from one total to another
tablethe full placement slip, with every line and every term