(Adds TMX, IAG, OC Oerlikon, Oyak, Teva, United Technologies, WPX Energy, Allianz, Pfizer)
July 14 (Reuters) - The following bids, mergers, acquisitions and disposals were reported by 2000 GMT on Tuesday:
** China's state-backed Tsinghua Unigroup Ltd is preparing a $23 billion bid for U.S. memory chip maker Micron Technology Inc , in what would be the biggest Chinese takeover of a U.S. company, people familiar with the matter said.
** U.S. drugmaker Pfizer has offered concessions in a bid to win European Union regulatory approval for its $15 billion takeover of U.S. rival Hospira, the European Commission said on Tuesday.
** A proposed merger of the two largest U.S. generic drug makers drew fire on Tuesday from Consumers Union and seven other groups, who asked antitrust enforcers to stop Teva Pharmaceutical Industries Ltd's proposal to purchase Mylan NV, saying it would lead to higher prices and more drug shortages.
** A consortium led by German insurer Allianz has been selected as the preferred bidder for a 4.2 billion pound ($6.5 billion) investment in London's new so-called "super-sewer".
** Natural gas producer WPX Energy Inc agreed to buy privately held RKI Exploration & Production LLC for $2.35 billion, snapping up oil-rich assets in the Permian basin on the cheap amid a steep drop in crude prices.
** Digital Realty Trust Inc said it would buy private equity owned Telx Group Inc in a deal valued at about $1.89 billion to double its footprint in the rapidly growing business of renting out space to companies to run their data centers.
** IAC/InterActive Corp's Match Group, which owns Match.com, agreed to buy dating website PlentyOfFish for $575 million to push deeper into the lucrative mobile-based dating business, ahead of its planned public listing.
** IAG has gained European Union antitrust approval for its 1.3-billion-euro ($1.4 billion) bid for Irish carrier Aer Lingus after agreeing to make concessions to ease competition worries, the EU Commission said on Tuesday.
** The U.S. Defense Department said on Tuesday it was "closely monitoring" the potential sale of helicopter maker Sikorsky Aircraft by its parent company, United Technologies Corp and that it would evaluate any deal on a case-by-case basis.
** China's Bohai Leasing Co Ltd said it had agreed to buy 20 percent of U.S.-listed Avolon Holdings Ltd for $429 million, in the latest acquisition by a unit of aviation and shipping conglomerate HNA Group.
** Volvo has bought Polestar Performance AB, a company that takes the classic Swedish cars and turns them into high-performance versions for the road. Financial details of the deal announced by Volvo Cars were not disclosed.
** Geneva's Syz is buying Royal Bank of Canada's Swiss private bank for an undisclosed sum, a deal that it expects to help more than double its profit from 2017.
** Swiss technology group OC Oerlikon is launching the sale of its vacuum pumps unit as it streamlines its portfolio following the takeover of the coatings unit Metco from peer Sulzer in 2014, three people familiar with the transaction said.
** Turkey's largest private pension fund Oyak has agreed to buy German alumina products maker Almatis from Dubai International Capital (DIC), the company said in a statement on Tuesday.
** Delta Air Lines Inc has offered to invest in Japan's bankrupt Skymark Airlines Inc as part of a restructuring plan for the budget carrier, two people familiar with the proposal said.
** Barclays has hired Lazard to sell its retail banking business in Italy as the British bank presses ahead with the sale of European assets, a source with knowledge of the matter said.
** South Korea's Samsung Electro-Mechanics Co Ltd said it would exit more non-core businesses such as the manufacturing of modules to regulate supply of power to electronics devices as it seeks to narrow the company's focus.
** An affiliate of Qatar-based television network Al Jazeera has acquired Turkish satellite network Digiturk, a statement from the companies said. No sale amount was given for the deal.
** Canadian investor Prem Watsa's Fairfax India Holdings Corp plans to increase its stake in Indian financial services firm IIFL Holdings Ltd to up to 26 percent for $225 million through a share tender offer. \
** TMX Group Ltd said on Tuesday it has sold its investor relations and financial communications arm Equicom to National Public Relations, marking the first decisive move by the stock exchange operator since completing a strategic review.
** GIC Pte Ltd, Singapore's sovereign wealth fund, agreed to pay 132.4 million reais ($42 million) for a minority stake in a shopping mall controlled by Brazil's Aliansce Shopping Centers SA, the latest step in the fund's push into Latin America's largest economy.
** Brazilian steelmaker CSN said it was exploring various options to reduce its debt level, including asset sales, but was not involved in talks over which it would be legally obliged to inform the market.
$1 = 0.95 Swiss francs $1 = 3.13 Brazilian reais $1 = 34.02 baht Compiled by Kshitiz Goliya in Bengaluru