Originating cause

"Originating cause" is the broadest of the unifying factors commonly used in aggregation clauses, treating losses as a single claim where they can be traced back to a common underlying source even though the immediate events or acts differ.

Definition §

"Originating cause" is an aggregation trigger which, when included in a policy or reinsurance contract, deems multiple losses or claims to be a single loss or claim where they share a common originating cause. The phrase is materially wider than narrower formulations such as "single event" or "single act or omission" and is generally understood to capture root causes rather than only proximate ones. ^[1]

The distinction between an "event" and a "cause" was articulated by Lord Mustill in Axa Reinsurance (UK) plc v Field [1996] 1 WLR 1026. An event was described as something that happens at a particular time, at a particular place and in a particular way, whereas a cause is more open-textured and can stretch backwards in the chain of causation. The choice of one formulation over the other in a policy is therefore not stylistic but determinative of scope. ^[2]

In aggregation analysis the originating cause is sought by working backwards from the immediate claims and asking whether they can fairly be said to share a common underlying source. The cause may be a single act, a continuing state of affairs, a flawed system or process, or a particular individual whose conduct contaminates a number of otherwise unconnected transactions. ^[3]

Because of its breadth, originating cause wording is commonly seen in reinsurance, in catastrophe covers and in some directors' and officers' wordings. It is less common in the SRA Minimum Terms for solicitors' professional indemnity, which instead uses a composite of narrower triggers. ^[4]

Legal / Regulatory basis §

The leading English authority on the breadth of originating cause wording is Lloyds TSB General Insurance Holdings Ltd v Lloyds Bank Group Insurance Co Ltd [2003] UKHL 48. The House of Lords had to determine whether claims arising from the mis-selling of pension policies by Lloyds TSB's intermediaries could be aggregated under a reinsurance clause referring to a single originating cause or source. Their Lordships analysed the language carefully and accepted that "originating cause" was deliberately broad, intended to reach further back in the chain of causation than narrower formulations such as "event". On the facts, however, the House of Lords held that the various sales decisions of different advisers to different customers did not share a single originating cause sufficient to engage the clause, and the losses were not aggregated. ^[5]

The earlier House of Lords decision in Axa Reinsurance (UK) plc v Field remains the foundational authority on the event-cause distinction. The reinsurance contract used "event" wording at one level and "originating cause" wording at another. Lord Mustill held that the two phrases were not interchangeable: "event" was narrow and pointed to a particular happening at a particular time and place, whereas "cause" was wider. The judgment is routinely cited in subsequent aggregation cases. ^[6]

The Court of Appeal and the Commercial Court have applied these principles in a number of contexts. Caterpillar (NI) Ltd v John Holt & Co (Liverpool) Ltd [2013] EWCA Civ 1232 considered aggregation language outside the pure insurance context and reinforced that the precise wording controls the outcome. Standard Life Assurance Ltd v Oak Dedicated Ltd [2008] EWHC 222 (Comm) considered how unifying factors are identified in a financial services context. ^[7]

The Supreme Court decision in AIG Europe Ltd v Woodman [2017] UKSC 18 did not concern "originating cause" wording directly, but Lord Toulson's judgment on the related concept of a "series of related transactions" sits in the same body of law and is regularly read alongside Lloyds TSB v Lloyds Bank Group Insurance in modern aggregation argument. ^[8]

The Insurance Act 2015 does not specifically address aggregation but provides the general principles of fair presentation, warranties and terms within which aggregation clauses operate. ^[9]

How it works in practice §

When a policy aggregates by reference to an originating cause, claims handlers and coverage lawyers approach the question in two stages. The first stage identifies candidate causes by tracing each individual claim back through its causal chain. The second stage asks whether those chains share a common point of origin which is sufficiently specific to be described as a single cause rather than as a general state of affairs.

The candidate cause must usually be more than a background condition. A general statement such as "the firm's poor supervision" or "a culture of inadequate compliance" is unlikely on its own to satisfy the wording, because such descriptions can apply to almost any set of professional negligence claims. Instead the cause must be capable of being articulated with sufficient particularity that it would be recognised as the source of the relevant losses. ^[10]

The breadth of originating cause wording usually favours the insurer where the per-claim limit is the binding constraint, because aggregating many small claims into one collapses recovery to a single per-claim cap. Conversely it can favour the insured where the aggregate limit is the binding constraint, because a single claim consumes only one allocation of the aggregate and may leave more cover available for unrelated losses.

Originating cause wording also affects which policy year responds. Where a notifiable circumstance gives rise to multiple later claims, the deeming provisions in most wordings treat all claims arising from that circumstance as having been made when the circumstance was notified. Identifying the originating cause therefore identifies the responding policy.

Common variations §

The market uses several different formulations to capture the same broad idea. Some wordings refer simply to a "single originating cause", others to a "single originating cause, source or event", and still others to a "single source or originating cause". The precise drafting affects the analysis but the underlying intention is the same: to reach back to a common root.

Some wordings combine an originating cause trigger with other narrower triggers, such as a single event or a single act or omission, in order to ensure that aggregation engages at whichever level produces a connection on the facts. This composite drafting is common in reinsurance treaty wordings.

Reinsurance "hours clauses" provide an alternative, time-based mechanism for aggregating losses from a single occurrence or event and operate in a different way from originating cause wording. The two mechanisms are sometimes combined in a single treaty.

Where the policy contains no aggregation wording at all, the default position under English law is that each claim is a separate claim and is subject to its own per-claim limit and excess.

Example §

A national accountancy firm employs a senior partner who, over the course of several years, encourages junior staff to apply an aggressive but ultimately incorrect interpretation of a particular tax provision in advice given to clients. Some thirty corporate clients receive advice on this basis and subsequently suffer losses when HMRC successfully challenges the position.

The firm's professional indemnity policy contains aggregation wording referring to a single originating cause. The illustrative limits are £10,000,000 per claim and £20,000,000 in the aggregate, with a £100,000 excess per claim.

If the senior partner's incorrect interpretation is identified as the single originating cause, the thirty claims are treated as one claim. The insured pays one excess of £100,000, and recovery is capped at the per-claim limit of £10,000,000 — potentially leaving a significant shortfall if the total claims exceed that figure.

If, on the facts, the claims cannot be traced to a single originating cause because different partners gave different advice for different reasons, the claims may remain separate, each attracting its own excess and its own per-claim limit, subject only to the £20,000,000 aggregate.

These figures are illustrative; the actual outcome depends on the wording and the evidence.

See also §

• /wiki/aggregation-clause/ — the broader mechanism in which originating cause sits
• /wiki/series-of-related-transactions/ — narrower unifying factor analysed in AIG v Woodman
• /wiki/series-of-related-matters/ — related SRA MTC trigger
• /wiki/single-act-or-omission/ — narrower alternative
• /wiki/per-claim-limit/ — financial control that aggregation engages
• /wiki/aggregate-limit/ — the period-wide cap aggregation interacts with
• /wiki/professional-indemnity-insurance/ — the line of business in which aggregation is most heavily litigated

References §

1. ↑ Axa Reinsurance (UK) plc v Field [1996] 1 WLR 1026 (HL)
2. ↑ Lloyds TSB General Insurance Holdings Ltd v Lloyds Bank Group Insurance Co Ltd [2003] UKHL 48 — https://publications.parliament.uk/pa/ld200203/ldjudgmt/jd031106/lloyds-1.htm
3. ↑ AIG Europe Ltd v Woodman [2017] UKSC 18 — https://www.supremecourt.uk/cases/uksc-2016-0033.html
4. ↑ Caterpillar (NI) Ltd v John Holt & Co (Liverpool) Ltd [2013] EWCA Civ 1232 — https://www.bailii.org/ew/cases/EWCA/Civ/2013/1232.html
5. ↑ Standard Life Assurance Ltd v Oak Dedicated Ltd [2008] EWHC 222 (Comm)
6. ↑ Insurance Act 2015 — https://www.legislation.gov.uk/ukpga/2015/4