* Core EBITDA ex corp costs $551 mln vs forecast $531 mln
* Growth boosted by Colombia, Africa, mobile financial services
* Sticks to 2014 forecast (Adds CEO comment, detail, EBITDA comparison)
STOCKHOLM, July 16 (Reuters) - Emerging markets telecoms group Millicom on Wednesday reported an unexpected rise in second-quarter core profit, boosted in part by strong growth in Africa and in mobile banking, and repeated its outlook for 2014.
After years of expanding its mobile customer base in Latin America and Africa, Millicom has shifted its focus to selling existing customers higher value services like data, mobile financial services and cable TV.
That, and a push into online ventures like African home shopping site Jumia, has raised costs and pushed down profitability.
But the company aims to expand revenues to $9 billion annually by 2017 from $5.2 billion last year, making it a stand-out growth story in an industry where income for most operators has been flatlining.
"We saw an acceleration of the strong revenue growth achieved in Q1 taking our organic revenue growth in Q2 to 9 percent," CEO Hans-Holger Albrecht said in a statement.
"We are taking market share in Africa and I expect that to continue."
Earnings before interest, tax, depreciation and amortisation (EBITDA) and before corporate costs were $551 million against a forecast of $531 million in a Reuters poll and $540 million in the year-ago quarter.
After corporate costs, core profit was $479 million against$496 million in the year-ago quarter.
Reported revenues rose to $1.45 billion in line with expectations and a pro forma $1.36 billion a year ago, reflecting the full consolidation Millicom's Guatemala business, and equity accounting for Mauritius and the Online division.
The Latin America and Africa-focused operator repeated it expected sales to grow at a mid to high single digit rate adjusted for currency swings and a core profit margin at around 35 percent in 2014, after corporate costs.
Year-to-date revenue growth is running at 8.8 percent with the EBITDA margin at 33.5 percent after corporate costs. (Reporting by Simon Johnson and Sven Nordenstam; Editing by Alistair Scrutton)