How a Coverage Layer Sits Above an Attachment Point
A coverage layer protects against a specified band of loss. Its attachment point marks where that band begins: losses below that point do not reach the layer. The layer also has a limit, which is the maximum amount the layer can pay. Together, these two amounts determine the highest loss level the layer can cover.
For example, a hypothetical layer with an attachment point of $100,000 and a limit of $40,000 begins above $100,000 and can pay at most $40,000. Its covered band extends from $100,000 to $140,000. The $140,000 boundary is the exhaustion point: once the loss reaches that level, the layer has used its full limit.
The attachment point and the limit describe different things. The attachment point is a loss level; the limit is an amount the layer can pay. If \(A=\$100{,}000\) and \(L=\$40{,}000\), the layer does not stop at a loss of $40,000. It stops being able to pay additional amounts after the loss reaches $140,000.
A layer may be described as “$40,000 excess of $100,000” or “$40,000 xs $100,000.” In this wording, $100,000 is the attachment point and $40,000 is the layer limit. Always identify which number plays which role before calculating.
Finding the Covered Loss Band
The relationship between attachment, limit, and exhaustion follows from adding the amount of loss the layer can cover to the point where it starts. If the layer begins at \(A\) and can cover \(L\) dollars, its upper boundary must be \(A+L\). The distance from \(A\) to that upper boundary is exactly \(L\):
This is also why the maximum payment is the layer limit. A loss that reaches or exceeds the exhaustion point has passed through the entire band, whose width is \(L\). Below the attachment point, none of the loss reaches the band. Between the two boundaries, only part of the band is reached.
The term “above the attachment point” matters at the boundary. At a loss of exactly \(A\), there is no loss above \(A\), so the layer has not yet paid. At exactly \(A+L\), the entire layer has been reached, so it can pay its full limit. A larger loss does not increase this layer’s payment; the layer is exhausted.
Determine whether the attachment applies to an individual loss, an occurrence total, or another stated measure. Use the loss amount on that basis.
Record the attachment point \(A\) as the lower boundary and the limit \(L\) as the maximum amount available from the layer.
Add the limit to the attachment point: \(A+L\). This is the loss level at which the layer is fully used.
A loss at or below \(A\) does not reach the layer. A loss between \(A\) and \(A+L\) reaches part of it. A loss at or above \(A+L\) reaches the full limit.
Worked Examples
Worked Example: Identifying the Band for a Single Loss
A hypothetical insurer buys a layer that covers one individual loss, with a $30,000 limit excess of $70,000. There is no coinsurance, and no other term reduces the layer’s payment. For losses of $58,000, $88,000, and $112,000, identify whether the layer is reached and determine its payment.
Method. Interpret “$30,000 excess of $70,000” as attachment point \(A=\$70{,}000\) and limit \(L=\$30{,}000\). First find the exhaustion point:
The layer’s covered band runs from $70,000 to $100,000. Its maximum payment is $30,000.
Loss of $58,000. This is below the $70,000 attachment point, so the loss does not reach the layer. Payment: $0.
Loss of $88,000. The portion above the attachment point is $88,000 − $70,000 = $18,000. This is less than the $30,000 limit, so the layer pays $18,000.
Loss of $112,000. The loss reaches beyond the $100,000 exhaustion point. The layer is fully used and pays its $30,000 limit, not the entire $42,000 by which the loss exceeds $70,000.
Check. The three payments are $0, $18,000, and $30,000. None exceeds the $30,000 limit, and the loss below attachment produces no layer payment. The common mistake avoided here is treating the $30,000 limit as the loss level where coverage ends; the correct upper boundary is $70,000 + $30,000 = $100,000.
Worked Example: Applying an Occurrence Attachment
A hypothetical reinsurance contract covers the total covered loss from each occurrence, with a $40,000 limit excess of $75,000. A single occurrence produces three covered claims of $32,000, $27,000, and $38,000. Assume the claims are grouped into this occurrence as stated, there is no coinsurance, and the layer applies once to the occurrence total. What does the layer pay?
Method. Because the attachment is per occurrence, add the claims before comparing the loss with the attachment point.
Occurrence loss:
The attachment point is \(A=\$75{,}000\), and the layer limit is \(L=\$40{,}000\). The exhaustion point is:
The occurrence loss of $97,000 is $22,000 above the attachment:
Because $22,000 is less than the $40,000 limit, the layer pays $22,000. It is not exhausted; $18,000 of its limit remains unused.
Check. The layer payment plus the loss below attachment is $22,000 + $75,000 = $97,000, the occurrence total. The result also falls below the $40,000 maximum. The common mistake avoided is applying the $75,000 attachment separately to each claim even though the contract attaches per occurrence.
Worked Example: Distinguishing the Layer Limit From Loss Above the Layer
A hypothetical commercial property program includes a layer of $250,000 excess of $600,000 on each covered event. An event produces a covered loss of $910,000. Assume the layer pays the full amount of loss in its band, has no coinsurance, and has no reinstatement. Determine the layer’s exhaustion point, payment, and the amount of this event loss above the layer.
Method. The attachment point is \(A=\$600{,}000\), and the limit is \(L=\$250{,}000\). The exhaustion point is:
The event loss reaches $910,000, which is $60,000 above the exhaustion point:
Since the event loss reaches beyond the top of the layer, the layer pays its full $250,000 limit. The $60,000 above the exhaustion point is not an additional payment from this layer. This calculation identifies only this layer’s payment; it does not determine whether some other contract responds to loss outside this band.
Check. The layer covers a band $250,000 wide, from $600,000 through $850,000, and pays at most $250,000. The $910,000 loss is high enough to exhaust the band, so payment is $250,000. The common mistake avoided is paying $310,000, the amount by which $910,000 exceeds the attachment; that exceeds the layer’s stated limit.
Interpreting Layer Terms Carefully
A layer’s attachment point is often described as the amount of loss that must be borne below the layer before it responds. This makes it similar in arithmetic effect to a deductible in some settings, but the terms describe different roles in a coverage structure. A deductible is a policy term applied to a loss under that policy; an attachment point locates a layer above a specified amount of loss. Do not infer that the underlying contract’s deductible, limit, or claim-handling rules are identical to the layer’s attachment terms.
The loss basis is just as important as the dollar amounts. An attachment can apply per loss or per occurrence, among other possible designs. For a per-loss layer, compare each loss separately with the attachment. For a per-occurrence layer, first form the covered occurrence total, then compare that total with the attachment. The same numerical attachment and limit can therefore produce different results if the loss basis changes.
When reading a layer description, check these points before calculating:
- Which amount is the attachment? In “$L excess of $A,” \(A\) is the attachment and \(L\) is the limit.
- What loss is being tested? Use the individual loss or occurrence total required by the contract wording.
- Where is the top of the band? Add the attachment and the layer limit.
- Has the layer been reached or exhausted? A loss below attachment does not reach it; a loss at or above the exhaustion point reaches its maximum.
- Are there modifying terms? Coinsurance, exclusions, aggregate caps, or other provisions can change the actual payment. The simple interpretation here assumes none applies.
Check Your Understanding
For each problem, identify the attachment point, limit, and relevant loss basis before deciding whether the layer responds.
- A hypothetical layer is $18,000 excess of $52,000 per loss. A covered loss is $49,500. State the exhaustion point and the layer payment. (Answer: Exhaustion point $70,000; payment $0.)
- A hypothetical per-loss layer is $26,000 excess of $64,000. A covered loss is $81,000. How much does the layer pay, and how much of its limit remains? (Answer: Payment $17,000; unused limit $9,000.)
- A hypothetical per-occurrence layer is $35,000 excess of $90,000. One occurrence has covered claims of $44,000 and $51,000. What is the occurrence total and the layer payment? (Answer: Occurrence total $95,000; payment $5,000.)
- A hypothetical event layer is $120,000 excess of $280,000. The event loss is $430,000. Find the exhaustion point and the layer payment. (Answer: Exhaustion point $400,000; payment $120,000.)
- A hypothetical per-occurrence layer is $50,000 excess of $150,000. An occurrence has covered claims of $82,000, $74,000, and $69,000. Determine whether the layer is exhausted and its payment. (Answer: Occurrence total $225,000; exhaustion point $200,000; the layer is exhausted and pays $50,000.)