BUENOS AIRES, May 14 (Reuters) - Argentina's stock, currency and bond market trends on Friday.
* The MerVal stocks index .MERV fell for a third straight session, retreating 0.65 percent to close at 1,438.64 points, tracking losses in regional markets.
* Index heavyweight Tenaris (TENA.BA), which makes steel tubes for the global energy industry, shed 1.56 percent to 50.4 pesos a share.
* On the broad stock market, volume was light at $12.6 million. Of active issues, 35 advanced, 33 declined and 10 were unchanged.
* Prices for government bonds traded over-the-counter in Buenos Aires gained 1.3 percent on average, climbing for a second day.
* The dollar-denominated Par bond ARPARD=RASL rose 4.4 percent to an ask price of 20.80.
* In formal exchange between banks, the Argentine peso closed 0.07 percent lower at 3.7275/3.723 per dollar ARS=RASL and the central bank sold dollars in the market to keep the peso from weakening further, traders said. The peso is currently hovering near a 7-year low.
* In informal trade between foreign exchange houses, as measured by Reuters, the peso rose 0.26 percent to 3.7725/3.775 ARSB=. (Reporting by Jorge Otaola and Walter Bianchi; Writing by Kevin Gray; Editing by Dan Grebler)