Deals of the day-Mergers and acquisitions

(Adds Hudson's Bay and Barnes & Nobles; Updates Salesforce, Comstock)

June 10 (Reuters) - The following bids, mergers, acquisitions and disposals were reported by 2030 GMT on Monday:

** Salesforce.com Inc agreed to buy big data firm Tableau Software Inc for $15.3 billion, adding muscle in its fight with Microsoft Corp for a bigger share of the market that helps businesses target customers with tools to analyze and visualize data.

** Dallas Cowboys owner Jerry Jones strengthened his company Comstock Resources Inc's grip on one of the largest natural gas basins in the United States with a $1.1 billion deal to buy privately held Covey Park.

** Swiss drugmaker Roche's $4.3 billion takeover of U.S. gene therapy specialist Spark Therapeutics has been pushed back again, possibly beyond the first half, as regulators continue to scrutinize the deal for its effect on competition.

** Drugmaker Merck & Co Inc said it agreed to buy privately held Tilos Therapeutics for up to $773 million, bolstering its pipeline of drugs to treat cancer and autoimmune diseases.

** Private equity firm Apollo Global Management LLC is in the lead to acquire Shutterfly Inc after making the highest offer for the digital imaging company, people familiar with the matter said.

** Millennium & Copthorne Hotels Plc has agreed to be acquired by majority owner City Developments Ltd (CDL) in a deal that values the British company at 2.23 billion pounds ($2.84 billion), the companies said.

** United Technologies Corp agreed to combine its aerospace business with U.S. contractor Raytheon Co and create a new company worth about $121 billion, in what would be the sector's biggest ever merger.

** British commercial property developer Helical Plc confirmed it had received buyout approaches from various parties but said the offers undervalued the company.

** The world's oldest travel company Thomas Cook edged closer to a break up after its biggest shareholder, China's Fosun Tourism, made a preliminary approach for the British group's core holiday operations.

** Hudson's Bay Co Executive Chairman Richard Baker teamed up with other shareholders and offered to take the struggling Canadian retailer private in a C$1.74 billion cash deal.

** Book distribution company Readerlink LLC is working towards making a bid for Barnes & Nobles Inc that would top hedge fund Elliott Management Corp's agreed price to buy the U.S bookseller, the Wall Street Journal reported, citing a source. (Compiled by Aakash Jagadeesh Babu in Bengaluru)