Abu Dhabi’s sovereign wealth fund has written off its 9.9% stake in Thames Water, citing a challenging regulatory environment and poor operational performance. This comes as the UK government tries to attract institutional investors to large infrastructure projects. Investors worry about tough regulations, as seen when Ofwat, the sector’s regulator, limited water companies’ ability to raise bills. Thames Water, burdened by £19bn in debt, needs at least £3bn in new equity to avoid running out of cash and possible re-nationalization. Existing investors, including Abu Dhabi, have resisted further funding, taking significant losses.