BUENOS AIRES, April 23 (Reuters) - Argentina's stock, currency and bond market trends on Thursday:
* The MerVal stocks index .MERV inched up 0.1 percent to 1,228.29 points in light, selective trade, accumulating a gain of 2.96 percent in the last three sessions.
* Local shares of Brazilian energy firm Petrobras (APBR.BA) drove the gains, rising 1.97 percent to 62.2 pesos per share. Index heavyweight Tenaris (TENA.BA)(TS.N) fell 0.22 percent on profit-taking, traders said.
* On the broader market, volume was thin at $11.1 million. Of active issues 35 declined, 29 advanced and 18 were unchanged.
* Prices for government bonds traded over the counter in Buenos Aires rose slightly for a third consecutive day, gaining 0.4 percent on average in cautious trade marked by the volatility of Wall Street.
* Dollar-denominated 2011 Bonar bonds ARBONAR11D=RASL gained 3.0 percent, according to the ask price.
* In formal exchange between banks, the peso was stable at 3.695/3.6975 per dollar ARS=RASL due to a balance between the supply and demand of greenbacks in the market.
* In informal trade between foreign exchange houses as measured by Reuters, the peso was also unchanged at 3.7375/3.7425 ARSB=. (Reporting by Walter Bianchi and Jorge Otaola; Writing by Helen Popper; Editing by Dan Grebler)