MANILA (Reuters) — Four main candidates are vying for the Philippine presidency in May's election, but no clear favorite, in part because the incumbent is not running and also because the candidates have not fully revealed their platforms. Analysts say the presidential race will hurt local markets in a big way if the elections do not produce credible results, while a smooth transition of power will likely boost investments in local stocks and bonds.

Here are some questions and answers on major economic and political issues markets want the top four presidential candidates to address:

HOW WILL YOU TACKLE CORRUPTION?

BENIGNO AQUINO — Aquino's phenomenal rise in popularity polls can be traced to an outpouring of emotion after the death of his mother, the country's revered democracy icon Corazon Aquino, in August 2009 and his campaign promise to fight corruption in government.

He vowed in his political ads and on his website to be the country's first and most determined corruption fighter, but has not given much details. In his first address to the business community last month, Aquino said he plans to develop a scorecard to assess various infrastructure projects against benchmarks transparent to the public.

Unlike his other main rivals, he has not been involved in any corruption scandal and has lived simply in the same house he grew up in.

MANUEL VILLAR — Billionaire lawmaker Villar, who has caught up with Aquino's ratings in the latest opinion poll, has been linked to a multi-million dollar infrastructure project allegedly inserted in the national budget. His opponents say the project was aimed at benefitting his family's property companies under Vista Land & Lifescapes.

He promises to fight graft, which he said has contributed to poor delivery of services and bad infrastructure, but also has not given details.

JOSEPH ESTRADA — Former president Estrada was ousted from office in 2001, later convicted of plunder and then pardoned by President Arroyo. He has denied any wrongdoing and has vowed to fight corruption and nepotism.

GILBERTO TEODORO — Although former defense chief Gilberto Teodoro has never been involved in any irregularity, his close association with Mrs. Arroyo, who has been hounded by allegations of corruption issues since 2005, weighs him down.

During his term as defense chief, Teodoro stopped several multi-million dollar deals, including the acquisition of combat helicopters and munitions for mortars, grenade launchers and helicopter gunships due to allegations of bribery and contract fixing. He has said corruption in government can only be minimized, not eradicated, through a carrot-and-stick approach.

HOW WILL YOU LIFT STATE REVENUES?

AQUINO — Aquino has an economics degree but no experience as an economist. He has said he would not impose new taxes or increase tax rates, and simply improve on revenue collection with more serious implementation of existing measures to curb and punish tax cheats and smugglers.

He said he would pursue the rationalization of fiscal incentives given to investors as part of his vision of low tax rates for all.
But analysts are nervous about how exactly he will tackle the revenue shortfall given his little executive or managerial experience and the tough task of cleaning up corruption and red tape at the revenue agencies.

VILLAR — Villar has vowed to be prudent in state spending to cut the budget deficit, now at record levels, and raise revenues. He has said tax collections can be improved by strengthening an existing rewards system to encourage revenue agencies to meet their targets. He also supports the rationalization of fiscal incentives.

ESTRADA — Estrada has not given details on his fiscal program but in his short-lived presidency during the Asian financial crisis, he kept a tight rein on spending to limit the fiscal shortfall.

TEODORO — Teodoro is widely expected to continue the current government's fiscal program, but he has said he will push back by a year to 2014 a goal to balance the budget. He said he would keep the 12 percent sales tax and improve on tax collection efficiency but gave no details on how he would do it.

He said he would favor borrowing more to finance the country's budget deficit if credit conditions were favourable.

HOW WILL YOU ADDRESS SECURITY ISSUES?

AQUINO — In his website, Aquino said he will pursue a broadly supported peace deal with Muslim rebels that will address decades of neglect. His running mate and the leader of his political party, Senator Manuel Roxas III, opposed a government deal expanding the autonomy for Muslims that led to an escalation of conflict in Mindanao in 2008.

VILLAR — He has said in public debates that poverty is the root of the peace and order problem in Southern Mindanao. He said state resources must be poured into the region if the government was serious in uplifting the lives of people in Mindano.

ESTRADA — He advocated iron-fisted policies to defeat communist and secessionist rebels during his administration and is expected to assume the same stance when elected.

TEODORO — As a former defence secretary, Teodoro is well placed to tackle the communist and Muslim insurgency issues.

Like all the other candidates, he favors holding peace talks to end the insurgencies that have killed more than 160,000 people and displaced two million. He has also said the government must invest in increased police and military visibility in Mindanao to eradicate private armies.(Reporting by Manny Mogato and Rosemarie Francisco)