Lloyd`s Confidential Index is a very useful source of data on the fleets of individual shipowners. Published twice-yearly since 1884, Lloyd`s Confidential Index is intended to help underwriters assess the risk of insuring an individual company`s ships. However, it has much information of value to the ship historian.

Lloyd`s Confidential Index is organised by owner, giving:

names, including subsidiaries
address
date when first listed in Lloyd`s Confidential Index
the number of ships sold or otherwise transferred (dropped in 1965)
a list of the current fleet, showing for each ship:
- the year and country where built
- tonnages [definition]
- classification society
- flag
- year acquired
- previous names
- details of voyages for vessels in foreign trade until 1920, and after that, a broad indication of where it is trading
- master`s [definition] name (until 1920)
a list of the owner`s ships totally lost in recent years with brief details of the casualty.

Until 1920 Lloyd`s Confidential Index listed only British owners with steamers over 100 tons and sailing vessels over 500 tons (with separate volumes for steam and sailing vessels). Since 1921 owners of foreign vessels over 1,000 tons have been included, first in a separate volume and since 1966 combined into one volume. In 1921, the lower limit for all British ships was set at 500 tons.

The publishers of Lloyd`s Confidential Index prohibit the use of a volume by members of the public until thirty years after publication. Isolated copies can be found in a few libraries, with the Guildhall Library [address] having a full set of those accessible to the public. The World Ship Society [address] has a small collection.