March 23 (Reuters) - The following are the top stories in the Wall Street Journal. Reuters has not verified these stories and does not vouch for their accuracy.

* Tenet Healthcare Corp is nearing a deal to buy United Surgical Partners International Inc as a number of hospital networks seek mergers amid sweeping changes in the U.S. healthcare system. (http://on.wsj.com/1LM0jsA)

* China National Chemical Corp and other investors are making a bid for Pirelli & C SpA that could value the Italian tire maker at around $7.7 billion - one of the largest overseas acquisitions by a Chinese state firm in recent years. (http://on.wsj.com/1FQFzuJ)

* RadioShack Corp's fate hangs in the balance Monday when a bankruptcy auction kicks off, pitting companies that want to liquidate the electronic retailer's remaining assets against a hedge fund that has pledged to keep about half the chain's stores open. (http://on.wsj.com/1LMhaM3)

* In an escalation of its fight with a group of large mortgage investors, Ocwen Financial Corp issued a lengthy rebuttal of claims that the company was responsible for poor mortgage-servicing practices. (http://on.wsj.com/1N4hMYL)

* Fortescue Metals Group's Chief Executive Nev Power said Monday the iron-ore miner was under no time pressure to secure a refinancing of its debt, a week after it had to scrap plans for a $2.5 billion bond issue. (http://on.wsj.com/1GJmPM9) (Compiled by Rishika Sadam in Bengaluru)