BUENOS AIRES, Aug 26 (Reuters) - Argentina's stock, currency and bond market trends on Wednesday.
* MerVal stocks index .MERV fell slightly, off 0.08 percent to 1,778.26 points -- the third consecutive drop -- as a fall in global oil prices affected some heavyweight stocks.
* Buenos Aires-listed shares of Brazilian energy company Petrobras de Brasil APBR.BA (PETR4.SA) fell 1.31 percent to end at 83.00. Petrobras is weighted as 13.62 percent of the MerVal.
* On the broad market stocks volume was low at $9.0 million. Of active issues, 22 advanced, 34 declined and 19 were unchanged.
* Prices for government bonds traded over-the-counter in Buenos Aires fell 1.3 percent on average as investors took profits after several days of rising prices ahead of a government swap of inflation-linked bonds on Friday.
* The peso-denominated 2038 Par bond ARPARP=RASL plunged 5.8 percent to end at 24.40.
* In formal exchange between banks the peso strengthened 0.06 percent to end at 3.8475/3.8500 per dollar ARS=RASL.
* In informal trade between foreign exchange houses, as measured by Reuters, the peso weakened 0.06 percent to end at 3.8575/3.8625 ARSB=. (Reporting by Walter Bianchi and Jorge Otaola. Writing by Luis Andres Henao; Editing by Dan Grebler)