* Revenue rises faster than costs

* Cost synergies from Globex buyout to top estimates

* Financial expenses tumble on lower rates

* Margins strained by growth strategy (Recasts to add cost synergies guidance, CFO comments)

By Guillermo Parra-Bernal

SAO PAULO, Nov 12 (Reuters) - Brazilian retailer Grupo Pao de Acucar (PCAR5.SA: Quote, Profile, Research)(CBD.N: Quote, Profile, Research) said third-quarter net income more than doubled from a year earlier as sales rose faster than costs and debt-servicing expenses declined.

Grupo Pao de Acucar, Brazil's largest supermarket chain, reported on Thursday quarterly net income of 171 million reais ($99 million), up 157 percent from 66.6 million reais a year earlier, according to a securities filing. In the second quarter, profit was 131.7 million reais.

Results of Pao de Acucar add to evidence that the consumer market in Latin America's largest economy has become the main engine of economic expansion, helping pull the country out of recession faster than other major peers.

Expansion will continue next year to take advantage of a consumer sector that is growing at a faster pace than the overall economy. Chief Financial Officer Eneas Pestana said on a conference call with analysts after the release that capital expenditures for 2010 will likely top this year's guidance of 750 million reais.