"Sharing" is a matter of pooling the resource and allocating it without necessarily calculating everyone's individual benefit in discrete units. By contrast, "mutualization" is a more precisely qualified or quantified benefit, usually based on some predetermined formula or agreement. In the commons it is essential that these agreements are made by those who have a direct stake in the resource system.
While Pool & Share works in countless circumstances, Cap & Share or Mutualize is particularly useful for sharing collective resources that are limited and depletable. Establishing a "cap" on usage limits over-exploitation, as does refusing to trade them as a commodity. Sharing or mutualizing a resource not only helps to reduce pressure on over-exploitation, it helps assure a rough equity in access to and use of it.
# Why Cap & Share or Mutualize but Don't Trade?
We believe that Cap & Share or Mutualize is far superior to/more powerful than the Cap & Trade approach. When markets or bureaucracies use a policy regime that is disconnected from on-the-ground ecological realities -- e.g., ignorant of the actual carrying capacity of an ecosystem or reliant on politically motivated or arbitrary usage caps -- ordinary people will not heed ecological realities. They will instead respond to the bureaucratic rules or market signals, which are often beside the point. A prime example is fishery quotas set by government agencies, which are often not respected by fisherpeople and violated.
Storify - we would need to add two examples: One on how "cap and trade" is being ignored or undermined (there are many of them) and the other one how cap & Share or mutualize works And this is actually very common: We could take irrigation systems, they all cap and share. It would just be great to take a very old and still working one -> Stwitzerland/ Italy or the acequias in Mexico... just one, but one we can storify
# Examples
Cap & Share or Mutualize is arguably the most prevalent pattern of commoning in the world today. The International Land Coalition estimates that up to 3 billion people around the world rely on about 8 billion hectares of land governed by traditional, community based ownership systems webpage 
, which tend to be systems of Cap & Share or Mutualize.
discuss this example and also the following elements, which I think contribute to make the distinction in terms of value and philosophy very clear.
# How is this Different from Cap & Trade?
- Caps are decided upon directly by the users themselves, not remote third parties like governments or international bodies. - Trading and the quest for competitive advantage often induces corruption. Mutualizing tends to prevent it. - The cultural ethic that arises within cap-and-share commons deters the libertarian, free-for-all ethic of individualism that markets encourage.
# See also: Stint & Allocate, Ecosystem Guilds