What is a line slip?

Some risks in the London Market are too complex, too large, or too specialist for a single insurer to negotiate and accept alone.

Rather than approaching every following underwriter individually for every risk, the market has developed a mechanism that allows one underwriter to act on behalf of others: the line slip.

A line slip is a form of delegated authority agreement. It allows a lead underwriter to accept risks within pre-agreed terms on behalf of a group of following underwriters, without each of them needing to negotiate or sign off on every individual risk.

Understanding how line slips work matters not only for placing business efficiently, but for making sure risk information flows correctly to everyone who carries a share of that risk.

Why line slips exist

The London Market has long operated on a subscription basis, where multiple underwriters each take a share of the same risk rather than one insurer accepting it in full.

For straightforward risks, this works well through direct negotiation. But for certain types of business, such as complex marine, energy, or catastrophe-exposed risks, negotiating separately with every following underwriter for every individual risk would be slow and impractical.

A line slip solves this by allowing a lead underwriter to accept risks on behalf of a defined panel of following underwriters, provided those risks fall within terms agreed in advance. The lead exercises judgement on individual risks; the following underwriters accept a pre-agreed share of whatever the lead agrees, within the scope of the slip.

This allows brokers to place business quickly, while still spreading the risk across multiple capacity providers.

How line slips have traditionally been structured

A line slip is typically documented as a standalone agreement setting out:

• The scope of business it covers (for example, a class of risk, geography or type of insured).
• The lead underwriter's authority limits.
• The following underwriters and their respective shares.
• The duration of the agreement.
• Reporting obligations between the lead and the following market.

A broker usually presents individual risks to the lead underwriter, who assesses and accepts them on behalf of the whole panel, within the agreed scope. The lead then reports the risk details to the following underwriters, who rely on this information for their own records, exposure management and regulatory reporting.

Because the following underwriters are not involved in each individual underwriting decision, the quality and timeliness of the lead's reporting back to them is central to how well the arrangement works in practice.

Line slips versus binder agreements

Line slips are sometimes confused with binder agreements, but the two serve different purposes.

A binder agreement is typically between an insurer (or group of insurers) and a coverholder, authorising the coverholder to write business and bind cover on the insurer's behalf, often for a defined class of business in a particular territory.

A line slip, by contrast, usually operates within the subscription market itself. It authorises a lead underwriter to bind risks on behalf of following underwriters, rather than delegating authority to an external coverholder.

The key distinction is who is delegating authority to whom: a binder delegates from insurer to coverholder, while a line slip delegates from following underwriters to a lead underwriter within the same market.

Where AI helps

Line slips are fundamentally a market structure and authority arrangement, not a technology problem, so AI does not change how the arrangement itself works.

What AI can support is the flow of data that results from a line slip: helping following underwriters receive risk information from the lead in a consistent, structured way, and helping oversight teams aggregate exposure across a panel more efficiently.

This does not remove the need for lead underwriters to exercise underwriting judgement, or for following underwriters to maintain oversight of the business written on their behalf. It simply reduces the manual effort involved in interpreting and consolidating reporting from the lead.

Example

A Lloyd's managing agent leads a line slip for a group of marine cargo risks, with several following syndicates participating under agreed terms.

A broker presents individual risks to the lead underwriter, who accepts them on behalf of all participating syndicates within the pre-agreed scope.

Risks within the agreed scope are placed quickly without individual negotiation with each following underwriter, while all parties receive consistent risk information to support their own oversight and reporting obligations.

FAQs

• Is a line slip the same as a binder?

  Not exactly. Both are forms of delegated authority, but a line slip typically involves a lead underwriter accepting risks on behalf of following underwriters in a subscription arrangement, while a binder is generally an agreement between an insurer and a coverholder to write business on the insurer's behalf.

• Who is responsible for oversight under a line slip?

  Following underwriters retain oversight responsibility for the business written on their behalf, even though the lead underwriter exercises day-to-day authority to accept individual risks within the agreed terms.

• What kinds of risks are typically placed via a line slip?

  Line slips are commonly used for complex, high-value or specialist risks where subscription market participation is typical, such as certain marine, energy or catastrophe-exposed business.