Aggregate covers can also be linked to the cedants

Aggregate covers can also be linked to the cedant's gross premium income during a
12-month period, with limit and deductible expressed as percentages and amounts.
Such covers are then known as "stop loss" contracts.

Risks attaching basis
A basis under which reinsurance is provided for claims arising from policies
commencing during the period to which the reinsurance relates. The insurer knows
there is coverage during the whole policy period even if claims are only discovered
or made later on.
All claims from cedant underlying policies inception during the period of the
reinsurance contract are covered even if they occur after the expiration date of
the reinsurance contract. Any claims from cedant underlying policies incepting
outside the period of the reinsurance contract are not covered even if they occur
during the period of the reinsurance contract.
Losses occurring basis
A Reinsurance treaty under which all claims occurring during the period of the
contract, irrespective of when the underlying policies incepted, are covered. Any
losses occurring after the contract expiration date are not covered.
As opposed to claims-made or risks attaching contracts. Insurance coverage is
provided for losses occurring in the defined period. This is the usual basis of
cover for short tail business.
Claims-made basis
A policy which covers all claims reported to an insurer within the policy period
irrespective of when they occurred.
Contracts
Most of the above examples concern reinsurance contracts that cover more than one
policy (treaty). Reinsurance can also be purchased on a per policy basis, in which
case it is known as facultative reinsurance. Facultative reinsurance can be written
on either a quota share or excess of loss basis. Facultative reinsurance contracts
are commonly memorialized in relatively brief contracts known as facultative
certificates and often are used for large or unusual risks that do not fit within
standard reinsurance treaties due to their exclusions. The term of a facultative
agreement coincides with the term of the policy. Facultative reinsurance is usually
purchased by the insurance underwriter who underwrote the original insurance
policy, whereas treaty reinsurance is typically purchased by a senior executive at
the insurance company.
The reinsurer's liability will usually cover the whole lifetime of the original
insurance, once it is written. However the question arises of when either party can
choose to cease the reinsurance in respect of future new business. Reinsurance
treaties can either be written on a "continuous" or "term" basis. A continuous
contract has no predetermined end date, but generally either party can give 90 days
notice to cancel or amend the treaty for new business. A term agreement has a
built-in expiration date. It is common for insurers and reinsurers to have long-
term relationships that span many years. Reinsurance treaties are typically longer
documents than facultative certificates, containing many of their own terms that
are distinct from the terms of the direct insurance policies that they reinsure.