* Fitch is second major agency to revise Colombian outlook
* Colombia is at bottom rung of investment grade status
* Economic growth has shown signs of slowing in 2013
By Jack Kimball
BOGOTA, March 6 (Reuters) - Fitch ratings agency revised Colombia's outlook to positive on Wednesday, citing the country's increased resilience to external shocks and favorable debt dynamics, in a move that could pave the way for an upgrade in the future.
After 10 years crawling back from junk bond status, Colombia's strong economy and security advances against leftist rebels have helped the country pull itself to the lowest rung of the investment grade ladder given by Wall Street agencies.
Fitch became the second major ratings firm to revise Colombia's outlook to positive from stable after Standard & Poor's did it in August last year. In 2011, Fitch was the last ratings company to give Colombia back investment grade.
The agency affirmed Colombia's BBB-minus sovereign rating.
"As a result of continued international reserve accumulation, Fitch expects Colombia to become a net sovereign external creditor in 2013," Fitch said in a statement.
Standard & Poor's and Moody's Investors Service rate Colombia similarly to Fitch, at BBB-minus and Baa3, respectively. Moody's has a stable outlook on the credit.
"Excellent news ... A positive outlook is the step prior to a better rating," Finance Minister Mauricio Cardenas wrote in a message on Twitter after the Fitch's announcement.
Colombia, Latin America's No. 4 economy, lost the investment-grade ranking as a result of a 1999 economic crisis.
Fitch says Colombia's ratings are underpinned by prudent policies, a solid debt repayment record and a strong macroeconomic performance compared to its peers.
Colombia had external public sector debt worth $45.5 billion as of October 2012, according to central bank data, and has multilateral loans with institutions, including the World Bank.
The Andean country has attracted billions of dollars in foreign direct investment over the last decade, boosting oil and coal output, after U.S. military aid helped security forces deal crippling blows to leftist guerrillas and cocaine cartels.
A successful conclusion to on-going peace talks between the government and Marxist rebels, who have been fighting for five decades, would help bolster the economy whose growth rate is estimated to lose almost 2 percentage points per year due to the war.
"Fitch expects that Colombia's internal conflict will not materially constrain the positive investment and overall performance of the economy," the firm said.
Despite advances on the security front, Colombia remains a country with one of the biggest wealth gaps in the region and struggles to battle more decentralized drug gangs that have made the nation the world's top cocaine producer.
"Colombia's low GDP per capita, relatively weaker governance indicators in relation to investment grade peers and limited trade openness represent key credit weaknesses of the sovereign's credit profile," Fitch said.
The local economy has shown signs of weakness this year with feeble data in industrial production and retail sales, and problems in the coal sector which the central bank expects to cut into expansion in the first quarter.
Colombia is expected to have grown 3.6 percent last year versus 5.9 percent in 2011 while expansion is seen around 4 percent this year, according to the central bank.