U.S. institutional investors as a whole have increased their share of U.S. equity markets from holding 37.2% of total U.S. equities in 1980 to 51.4% of total U.S. equities in the year 2000. 

Institutional ownership of the largest 1,000 U.S. corporations has increased from 61.4% in 2000 to a peak of 69.4% in 2004, and dropped just slightly to 67.9% in 2005.

Other Highlights from 2007 Institutional Investment Report:

• The "activist" state and local pension funds have increased their percentage share of U.S. equity markets from 2.9% in 1980 to 9.8% in 2005. 
• The private trusteed corporate funds have declined in their percentage share of U.S. equity markets from 15.1% in 1980 to 12.3% in 2005.
• Pension funds as a whole held 32.6% of total institutional investor assets in 1980, which grew to 38.9% of total assets by 2005. 
• The biggest gainer in amassing institutional investor assets in the last 25 years is the category of open end mutual funds, which went from owning only 2.3% of total institutional assets in 1980 to 23.8% in 2005. 

Looking just at the largest 25 corporations, in 2005, there were four companies registering institutional investor ownership in excess of 70% compared with 2 in 2004 and one or none in all prior years.

"The rise in the institutional share of U.S. equity markets means that the economic power and clout of U.S. institutional investors — including the activist state and local pension funds — continues," says Dr. Carolyn Kay Brancato, Senior Fellow and Director Emeritus of The Conference Board Governance Center and co-author of the report, together with consultant Stephan Rabimov. 

Click here to view related charts and a detailed table from The  2007 Institutional Investment Report from The Conference Board.