Personal Stop Loss is a type of insurance policy which limits the losses of Names at Lloyd's of London

Lloyd's of London

Lloyd's, also known as Lloyd's of London, is a British insurance and reinsurance market. It serves as a partially mutualised marketplace where multiple financial backers, underwriters, or members, whether individuals or corporations, come together to pool and spread risk...

, all of whom did (and some of whom still do) underwrite with unlimited liability. Provided that the PSL responds to the claims made on it, the unlimited liability thereby becomes to some extent limited.

PSL policies are not always available at all. Some are available as "mutuals" and, in the event that the market suffers large losses, may be unable to respond to any great extent.