BLOCKHOLDER
Blockholder: translation
The owner of a large amount of a company's shares and/or bonds, or block. In terms of shares, these owners are often able to influence the company with the voting rights awarded with their holding.
For example, if a mutual fund held 10 million shares in a company or 10% of the shares outstanding, they would be a blockholder and have considerable influence over who is on the board of directors.