Oct 8 (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.
* U.S. stocks tumbled on escalating concerns about global growth prospects, especially in Europe, as new data showed deepening stresses in the continent's economy and remarks from a leading policy maker highlighted the lack of consensus in dealing with the slowdown. (http://on.wsj.com/1sckWDk)
* Turkey and the United States warned that a major Syrian border city was in imminent danger of falling to Islamic State, with the two countries putting the onus on the other to halt the extremist group's advance. (http://on.wsj.com/1qemBT0)
* Wal-Mart is cutting health insurance for another 30,000 part-time workers and raising premiums for its other employees, as U.S. corporations push to contain costs in the wake of the federal health-care law. (http://on.wsj.com/1t1VimL)
* Valeant Pharmaceuticals and activist investor William Ackman plan to boost their offer for Allergan Inc by $15 per share, trying to keep the Botox maker from striking a rival deal. (http://on.wsj.com/1pOvVxG)
* Puerto Rico is expected to sell up to $1.2 billion of notes this week to large banks that have agreed to hold the debt until it matures in June, forestalling the heavy selling that followed a March bond issue. (http://on.wsj.com/1y4ntme)
* Several companies that agreed this year to buy others have ended up as the prey - targeted by even bigger fish seeking to gobble them up before their own purchases close. (http://on.wsj.com/ZssINK)
* Ivan Glasenberg has been digging around for another big deal. The former coal trader, veteran deal maker and now one of the world's biggest mining moguls, has made his boldest move yet to expand trading and mining company Glencore. He approached Rio Tinto about a merger that could have created the world's biggest mining company. (http://on.wsj.com/1oPfq4c)
* Timothy Geithner, one of the highest-ranking government officials during the financial crisis, testified in federal court Tuesday that he thought a failure of American International Group Inc would have had catastrophic consequences. (http://on.wsj.com/1pOyzn8)
* The world's largest buyout firm will curb a controversial fee practice that is under scrutiny from regulators and investors. Blackstone Group LP, which manages $279 billion, no longer will pocket extra consulting fees when selling or taking public companies it owns, according to a written exchange between the company and one of its fund investors. (http://on.wsj.com/1yLEXVR) (Compiled by Supriya Kurane in Bangalore)