Editing Demutualization (section)

===Building societies===
{{details|Building society#1980s and 1990s}}
A [[building society]] is a form of mutual mortgage provision organization that emerged in the UK in the 19th century, for personal savings and home mortgages. For much of the 20th century, building societies had a large share of the retail savings market, and they had their zenith after the deregulation under the Building Societies Act 1986.
Following that Act, many of the larger societies, beginning with [[Abbey National]], the second largest, in 1989, and including the [[Halifax Building Society]], the largest, soon converted into joint stock banking companies, some of which were subsequently acquired by other banks. Many societies soon became targets of speculative "[[Carpetbagger#United Kingdom|carpetbaggers]]", who opened savings accounts in order to obtain a windfall, in cash or shares, in the event of demutualisation.
Most of the remaining societies, such as the [[Nationwide Building Society]], the largest remaining mutual, adopted [[Shareholder rights plan|poison pill]] clauses in their rules as a defense against carpetbaggers. These took the form of a charitable assignment provision that requires new members to assign any compensation from demutualization to charity.<ref>{{cite web|url=http://www.cbr.cam.ac.uk/fileadmin/user_upload/centre-for-business-research/downloads/working-papers/wp205.pdf|title=Mutuality and Corporate Governance: the Evolution of UK Building Societies Following Deregulation|publisher=ESRC Centre for Business Research, University of Cambridge|date=June 2001|access-date=2015-11-12|archive-date=2017-08-08|archive-url=https://web.archive.org/web/20170808072554/https://www.cbr.cam.ac.uk/fileadmin/user_upload/centre-for-business-research/downloads/working-papers/wp205.pdf|url-status=dead}}</ref>