From Wikipedia, the free encyclopedia
Pension funds are important shareholders of listed and private companies. They are especially important to the stock market where large institutional investors like the Ontario Teachers' Pension Plan dominate. The largest 300 pension funds collectively hold about $6 trillion in assets. In January 2008, The Economist reported that Morgan Stanley estimates that pension funds worldwide hold over US$20 trillion in assets, the largest for any category of investor ahead of mutual funds, insurance companies,currency reserves, sovereign wealth funds, hedge funds, or private equity.A pension fund is a pool of assets forming an independent legal entity that are bought with the contributions to a pension plan for the exclusive purpose of financing pension plan benefits.
Open vs. closed pension funds
Open pension funds support at least one pension plan with no restriction on membership while closed pension funds support only pension plans that are limited to certain employees.
Closed pension funds are further subclassified into:
- Single employer pension funds
- Multi-employer pension funds
- Related member pension funds
- Individual pension funds
Public vs. private pension funds
A public pension fund is one that is regulated under public sector law while a private pension fund is regulated under private sector law. In certain countries the distinction between public or government pension funds and private pension funds may be difficult to assess.
See main article, Superannuation in Australia
- Public Sector Superannuation Scheme (for federal civil servants)
- Commonwealth Superannuation Scheme (older scheme for federal civil servants)
- State Super (for New South Wales state civil servants)
- The Retail Employees Superannuation Trust (Australia's largest superannuation fund by membership)
- ANZ Australian Staff Superannuation Scheme (for employees of ANZ Bank)
- Ontario Teachers' Pension Plan (union-controlled)
- Hospitals of Ontario Pension Plan (HOOPP)
- OMERS Administration Corporation (OMERS)
- Ontario Pension Board (OPB)
- The Government Pension Fund - Global (Statens pensjonsfond - Utland)
- The Government Pension Fund - Norway (Statens pensjonsfond - Norge)
- California Public Employees' Retirement System (CalPERS)
- California State Teachers' Retirement System (CalSTRS)
- Federal Retirement Thrift Investment Board
- Fire and Police Pension Association of Colorado (FPPA)
- Illinois Municipal Retirement Fund
- Kansas City Public School Retirement System (KCPSRS)
- Kansas Public Employees Retirement System (KPERS)
- Minnesota Public Employees' Retirement Association (MNPERA)
- Minnesota Teachers' Retirement Association (MNTRA)
- New York State Teachers' Retirement System (NYSTRS)
- Retirement Systems of Alabama
- Teacher Retirement System of Texas (TRS of Texas)
- Public Employees Pension Fund 
Largest pension funds
Impact of the Development of Pension Funds
Pension Funds have played a major role in the emergence of truly global money flows, notably through their large-scale cross-border investments, channelling the excess long-term liquidities of G8 and OPEC countries towards both Western bourses andemerging markets, contributing to the development of a truly integrated and thus more efficient global financial sphere. 
But the impact of the development of pension funds on the global economy is sometimes viewed in some quarters as a contentious issue as national, domestic markets are further integrated and thus interconnected, which facilitates both cross-border investment in times of economic growth and abrupt capital flight in times of crisis. Many pension plans invest in mutual funds. In the US market, this is typically done through the 401k, 403B, IRA, or other IRS-approved and employer-sponsored retirement plans.
The relative size of pension funds could contribute to explaining the overall economic strength of developed countries such as e.g. Canada: Canadian pension funds (7 of which have more than C$100. billion under management) are powerful investors in both domestic and global financial markets with hundreds of billions of dollars in assets in an economy of only around one trillion dollars- some think-tanks such as the CEE Council have argued that this constitutes a long-term competitive advantage for the Canadian economy.