BUENOS AIRES, Aug 27 (Reuters) - Argentina's stock, currency and bond market trends on Thursday.
* MerVal stocks index .MERV closed flat at 1,778.34 points, with a slump in oil-related stocks compensated by gains by power companies.
* Among the biggest gainers was electric company Edenor (EDN.BA), rising 3.63 percent to 1.14 pesos per share. The local listing of Brazilian state-run energy firm Petrobras APBR.BA(PETR4.SA) fell 1.56 percent to 81.7 pesos per share.
* On the broad market stocks volume was low at $11.5 million. Of active issues 35 advanced, 19 declined and 17 were unchanged.
* Prices for government bonds traded over-the-counter in Buenos Aires fell 0.9 percent as investors took profits after several days of rising prices ahead of a government swap of inflation-linked bonds on Friday.
* The dollar-denominated 2038 Par bond ARPARD=RASL fell 2.6 percent to end at 27.90, according to the ask price.
* In formal exchange between banks the peso was flat at 3.8475/3.8500 per dollar ARS=RASL.
* In informal trade between foreign exchange houses, as measured by Reuters, the peso firmed slightly 0.06 percent to end at 3.855/3.8600 ARSB=. (Reporting by Walter Bianchi, writing by Luis Andres Henao)