This is a very common question, particularly if you're looking for free information.
Searching for trusts in the UK
If you know a trust is registered in England or Wales, it WILL be on the Charity Commission's 'Register of Charities'. Finding it within their database is another question entirely!
Searching the Charity Commission 'Register of Charities'
Although the search functions of the RoC database has improved over the years, it can often still be difficult to find the trust you're looking for, particularly if a trust has initials in its name. The database allows you to search by:
Unless you know the registered number, the most effective way to find the trust you're looking for is to use their 'Keyword(s)' facility. As a researcher, expanding the search criteria to as wide as possible might bring back more results, but means that what you're looking for will be there.
So, for example, if you were looking for The AL Sussman Charitable Trust, typing in Sussman into the 'Name Match' search box will not find the trust because it searches for names 'beginning with'. Instead, change the criteria to 'Keywords' and type in Sussman. This will result in finding The Adrienne and Leslie Sussman Charitable Trust. Try to always use KEY WORDS instead of common ones like 'The' or 'Charitable'.
If you still can't find the trust, some other things to think about when searching are:
If you're looking for a trust with a common name, like Smith, you'll need to widen the search parameters by clicking on 'limited to 500 records' instead of 200. Essentially what you're looking to do is ensure you have the greatest possible chance of locating the trust, especially if you're not absolutely certain of it's name and/or spelling.
If you still can't find the trust you're looking for, try searching the Guidestar website which also lists all registered charities.
Finding trusts and foundations in other countries
If you're not sure where the trust you're looking for is registered, try searching other charity registers and directories, including:
Scotland
Northern Ireland
Ireland
New Zealand
Switzerland
America
Asia
Global
Whilst this isn't an exhaustive list, it does give you some idea of how to find the information you want on trust and foundations. If you're looking for lists of trusts and foundations in specific countries, try first finding out if they have a charities commission or equivalent or search the government's revenue services.
Another good tip, especially when looking for funding, is to search for trust or foundation associations, where a list of members will reveal at least some of the foundations in that country/region. Why not start off by searching through the fResource Organsiations database, which lists many such umbrella organisations.