Institutional fund management is fund management conducted by large financial firms such as banks, insurance companies and major investment organisations (e.g. Fidelity or Vanguard).
In practice the ultimate owners of shares often do not exercise the power they collectively hold (e.g. because the owners are many and diverse each with small holdings), and the financial institutions (as agents) may or may not choose to do so. There is a general belief that shareholders, by which is often meant the institutions acting as agents, could and should exercise more active influence over the companies they hold shares in (e.g. to hold managements to account and to ensure that Boards function effectively). This would mean that there would be another effective pressure group (additional to the regulators and the Board) overseeing management.
Some institutions have been more vocal and more active in pursuing such matters than others. Some institutions have believed that there were investment advantages to building up substantial minority shareholdings (e.g. 10% or more) and then bringing pressure on managements to change the way firms were run. Another widespread tactic is for institutions to effectively collude to force management change. Perhaps more widespread is the sustained pressure that large institutions can bring to bear by talk and persuasion as they liaise with managements over time.
The national context in which shareholder representation considerations are set is variable and important. The USA is a litigious society and shareholders use the law as a lever to pressure managements. In Japan it is traditional for shareholders to be low in the 'pecking order' and for managements and work forces to some extent to operate as mini-clubs able to ignore the rights of the ultimate owners. In Japan we may say that there is more of a stakeholder mentality where it is felt appropriate to seek consensus amongst all interested parties against the background of strong unions and labour legislation.