C. Hoare & Co. is the sole survivor of the private deposit banks which were established in the 17th and 18th centuries. The bank has been owned and directed by members of the Hoare family since it was founded by Richard Hoare in 1672. The archive might be interest to researchers of the 17th to early 20th centuries, even if you don’t study financial history. For instance, a ledger showed a subscription generated in 1807 to fund William Wilberforce’s re-election to the House of Commons.
The archivist has written a guest blog about the archive and how to get access. See http://blogs.bodleian.ox.ac.uk/history/2014/05/28/c-hoare-and-co-archives/.