FACTBOX: Treasury possibilities for McCain, Obama

(Reuters) - While Republican presidential candidate John McCain and his Democratic rival, Barack Obama, are weighing options for vice presidential picks, Wall Street is speculating about who might be the next U.S. Treasury Secretary.

Here are some of the possibilities:

MCCAIN

* Martin Feldstein. Harvard economist and chief executive of the National Bureau of Economic Research, who told Reuters earlier this month: "I think we're heading for a recession." Feldstein believes housing is the key to recovery of the U.S. economy. He wrote recently in The Washington Post the government could create a loan program for homeowners that would act as a "circuit breaker" to reduce mortgage defaults and cut risk for sharp price declines. Feldstein was a chief economic adviser to Ronald Reagan.

* Carly Fiorina. Former Hewlett-Packard chief executive who was once considered the most powerful businesswoman in America and now is a top McCain economic adviser. She has voiced confidence in Federal Reserve Chairman Ben Bernanke and said McCain would pursue a strong dollar policy. Fiorina oversaw the 2002 merger of Hewlett-Packard Co and Compaq Computer Corp, then the biggest-ever technology merger. HP's poor performance forced her exit, with a $14 million severance deal. McCain has criticized excessive CEO pay and severance, and said he would push for reforms, if elected. Fiorina says her severance has been misconstrued by critics.

* Phil Gramm. Economist, former U.S. senator from Texas and a vice chairman for UBS Investment Bank is a McCain friend and senior adviser who helped resurrect his campaign. McCain calls him the smartest senator he has ever known. A deficit hawk, Gramm was a proponent of banking deregulation and co-authored legislation permitting banks to broadly diversify in financial services. Some experts believe diversification enabled conditions that contributed to the subprime crisis. Gramm says banks would be in worse shape without the change in law.

OBAMA

* Gov. Jon Corzine of New Jersey. Former U.S. senator from New Jersey and former chairman of investment house Goldman Sachs. One-time Hillary Clinton supporter who has stepped up work for Obama. Appeared in Chicago at an economic summit with Obama, and on a recent conference call, Corzine helped articulate the candidate's program to curb speculation in energy markets. Was seriously injured in a car crash in 2007.

* Timothy Geithner. New York Federal Reserve Bank chairman. Wrote recently in the Financial Times that banks crucial to the global financial system should operate under a unified regulatory framework. Former treasury undersecretary for international affairs during Clinton administration. Also held U.S. treasury post in Tokyo.

* Lawrence Summers. Economist. Former treasury secretary under Bill Clinton and former president of Harvard University. Summers' brief tenure at Harvard was marked by conflict with faculty and other controversy. Summers told Fortune this year the U.S. economy is resilient and he would be "very surprised" to see it supplanted as the leading global economy. He wrote in the Financial Times in April that interests of working people and the middle class must be more closely aligned in a global economy. Summers is also a former World Bank chief economist.

* Laura Tyson. Former chairwoman of Bill Clinton's Council of Economic Advisers who also served as his National Economic Council director. She is now a professor at the University of California, Berkeley and has only recently been tapped as a key adviser to Obama.

Sources: Washington Post, Financial Times, Fortune, New York Times, Dallas Morning News

(Editing by Eric Beech)

(For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)