Can we take the % of shares held by institutional owners or mutual funds / investment banks as proxy for shareholder activism due to non-availability of shareholders proposal data. Any suggestions or reference ?
Your expression "non-availabiity of shareholders proposal data" is unclear. No, "proxies" have nothing to do with activism. Their use is merely a sign of shareholder interest, and that is not activism. You might get a handle on activism by observing interventions of institutional investers at AGMs, be that by written submission or spoken question.
from a practitioner's point of view shareholders activities can be assessed based on the type of the companies. For publicly held companies we can see shareholders' activities in their presence in AGM as well as extra-ordinary general meeting, the questions they raise during the meeting and those which are presented in writing before the meetings based on countries' legal requirements. There are incidents in some AGMs where shareholders stop the approval of auditor's report and financial statements waiting further investigations or restatements of audited statements by the company's management. Also, how the share of the company I being dealt with in the stock markets can be seen as representing financial activity of shareholders. In other companies, some of the main shareholders can request separate meetings with the board of directors or the audit committee to discuss important affairs of the company. Also, the number of shareholders who represent other shareholders in the BOD is also another important feature of shareholders' activities. For private and family owned business, the level and extent of activities of shareholders is rather limited and restricted and based only in attending AGM and other official meetings. So you can select proxies for number of meetings both official and non-official, changes in value and quantities of shares in stock market, type and number of questions in meetings, number of shareholders represented in BOD and if you can get such details their activities within the BOD.