 |  | Murdoch opponent challenges UK regulator over Sky deal |  | LONDON (Reuters) - Activist group Avaaz stepped up its battle to stop Rupert Murdoch buying Sky , launching a legal challenge to the regulator's view that the pay-TV group would still be a "fit and proper" owner of a broadcasting license if the deal goes ahead. | |  |  |  | Tesla's big battery races to keep South Australia's lights on |  | HORNSDALE, Australia (Reuters) - One year after the state of South Australia suffered a major blackout, the clock has started ticking for Tesla Inc to finish building the world's biggest battery to help keep the lights on in Australia's most wind-dependent state. | |  | |  |  | |  |  | Related Video | |  | |  | |  |  |  |  |  | Make sense of the market with highlights of valuable financial information and reports along with compelling investment insights. Register Today |  | |  |  |  | The latest Reuters articles on M&A, IPOs, private equity, hedge funds and regulatory updates delivered to your inbox each day. Register Today |  | |  | » » MORE NEWSLETTERS |  | |