* 2015 profit to show impact of "extensive expenditure" -CFO
* Audi targets 2015 sales record, expects to outpace markets
* Sees "moderate" sales rise after 2014 record 53.8 bln eur (adds comments from analyst, R&D boss)
By Andreas Cremer
INGOLSTADT, Germany, March 10 (Reuters) - Audi's profit margins could fall again this year as it invests in its drive to overtake German rival BMW as the world's biggest seller of luxury cars, it said on Tuesday.
The forecast highlights the cut-throat battle at the premium end of the auto market, where Audi has sold more cars than BMW in the first two months of this year, but third-placed Mercedes-Benz is closing the gap on both of its bigger competitors.
Audi, the profit engine of Europe's biggest carmaker Volkswagen (VW), plans to expand its model range to 60 upmarket cars and sport-utility vehicles (SUV) by 2020 from 52 now, and is investing more than 1 billion euros ($1.1 billion) in new factories in Mexico and Brazil.
But the heavy spending is squeezing margins, at a time when the industry is fighting to attract buyers amid slowing demand in emerging markets and a sluggish recovery in Europe.
"Audi has been pushing discounts comparable to volume brands, they are hooked on the idea of becoming the top (luxury) seller," said Evercore ISI analyst Arndt Ellinghorst, who has a hold rating on VW stock.
Audi, source of about 40 percent of VW's group profit, said its operating profit margin slipped to 9.6 percent last year from 10.1 percent in 2013 and signalled it could fall again this year, while keeping its 8-10 percent target range.
Daimler's Mercedes-Benz reported a margin of 8.1 percent for 2014, while BMW has yet to publish the figure.
"We are shouldering massive upfront investments," Audi finance chief Axel Strotbek said at a press conference.
Evercore ISI's Ellinghorst forecasts Audi's profit margin could fall to 9.1 percent this year.
At 1445 GMT, VW shares were down 1.2 percent at 229.35 euros.
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BMW's sales lead over Audi shrank by 13 percent in 2014 to 70,000 cars, while Audi's own advantage over Mercedes fell by a fifth to 91,000 vehicles.
Despite its strong start to this year in terms of overall sales, Audi's growth rate is slowing, and it is to looking overhauls of the flagship Q7 SUV and the A3 compact series to restore momentum.
The brand said it expected to beat volume growth in world markets, predicting its car sales would set another record this year after 1.74 million deliveries in 2014.
Adding to the pressure on luxury carmakers is the need to invest in new technologies to reduce carbon emissions and in new software to meet the burgeoning demand for in-car information, entertainment and driving aids.
More than two years after abandoning electric cars, Audi is investing in the technology again and R&D boss Ulrich Hackenberg said it would launch an SUV with over 500 km of range by 2018, confirming what sources had told Reuters.
"These (fuel-efficient) endeavours are very heavy indeed" from the financial viewpoint, Hackenberg said.
VW said last month its operating margin might fall this year, although it kept its profit guidance.
($1 = 0.9289 euros) (Editing by Maria Sheahan and Mark Potter)