May 8 (Reuters) - The following were the top stories in the New York Times business pages on Thursday. Reuters has not verified these stories and does not vouch for their accuracy.
* A dozen oil companies agreed to pay $423 million in cash plus clean-up costs to settle litigation over groundwater contamination from the gasoline additive, MTBE.
* Under the aegis of the Federal Reserve, BlackRock Inc (BLK.N) is managing $30 billion of hard-to-sell assets from Bear Stearns Cos BSC.N. If it fumbles, the Fed, and by extension taxpayers, could lose billions.
* With its more rigorous oversight of airplane maintenance having led to the recent grounding of thousands of flights, the Federal Aviation Administration is confronting long-term questions about whether it should act more like a tough regulator, rather than a partner, of the airlines.
* A UBS AG UBSN.VX executive was briefly detained by U.S. authorities in connection with a widening investigation into the Swiss bank's work with questionable tax transactions.
* California has awarded $271 million in grants to build 12 stem cell research centers in the state, even as one of the political rationales for the building program might soon disappear.
* Citigroup Inc (C.N) said it was moving one of its most senior investment bankers to the Middle East, hoping to establish a stronger foothold in the oil-rich region.
* The chairmen of Delta Air Lines (DAL.N) and Northwest Airlines NWA.N said a merger was essential to preserve jobs and service to small cities, and to compete with foreign-flag carriers.
* Microsoft Corp (MSFT.O) is underwriting an online movie-making contest to stimulate sales and burnish the reputation of its Windows Vista operating system.
* Rainbow Media, the cable programming subsidiary of Cablevision CVC.N, said it was purchasing the Sundance Channel, which shows independent films and other programming, for $496 million in stock and cash.
* NBC Universal announced plans to start a 24-hour local cable news channel similar to New York 1. It will de-emphasize the identity of NBC's flagship station, WNBC, Channel 4, rechristening it a "content center" and making it one part of a larger media presence.
* A who's who of technology and telecommunications companies announced that it intended to build the first of a new generation of nationwide wireless data networks. The consortium includes a disparate group of partners -- Sprint Nextel (S.N), Google Inc (GOOG.O), Intel Corp (INTC.O), Comcast Corp (CMCSA.O), Time Warner Cable Inc (TWX.N) and Clearwire Corp CLWR.O
* Worker productivity rose by a better-than-expected amount in the first quarter; meanwhile, consumer borrowing rose in March at the fastest pace this year.