Example:

The government initiative included ***expanding the ownership base*** of publicly owned companies offered for privatization, opening dialogue with the private sector and expanding new areas of collaboration and mutual benefit.
http://www.fdi.gov.cn/pub/FDI_EN/98/Forum&Seminar/9th/World ...

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Note added at 30 mins (2008-06-19 03:07:05 GMT)
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alternatively: "broadening the ownership base" (same meaning). Example:

There are a number of policy issues with which African countries have to grapple in the process of privatization. The most urgent one is the issue of ***broadening the ownership base*** of privatized enterprises to be more inclusive of major national constituencies. If ownership is broadened, national aspirations are satisfied and political acceptance of the process is garnered.
http://www.uneca.org/eca_resources/Major_ECA_Websites/joint/...