BUENOS AIRES, May 4 (Reuters) - Argentina's stock, currency and bond market trends on Monday.
* The MerVal stocks index .MERV jumped 6.08 percent on global gains in bourses and crude oil, closing at 1,352.88, its highest level since mid-October.
* Brazilian state energy firm Petrobras APBR.BA surged 10 percent to 70.0 pesos a share, while Tenaris (TENA.BA) (TS.N) -- which makes steel tubes for the energy industry -- gained 7.8 percent to 51.2 pesos.
* These two companies account for 60 percent of the MerVal's weighting.
* Prices for government bonds traded over the counter in Buenos Aires rose 0.5 percent on average, with uncertainty ahead of a June mid-term election and worries over tight state financing tempering the impact of optimism in global markets.
* A source at the Economy Ministry told reporters on Monday the government had refinanced 8.45 billion pesos (some $2.3 billion) in debt owed to the state pension administrator, Anses, by issuing the agency a bond that matures in 2016.
* Dollar-denominated Discount bonds ARDISCD=RASL jumped 3.1 percent, according to the ask price.
* The Argentine peso mirrored the region's positive trend, firming 0.47 percent to 3.695/3.6975 per dollar in formal trade between banks ARS=RASL.
* In informal trade between foreign exchange houses as measured by Reuters, the peso gained 0.2 percent to end at 3.73/3.735 ARSB=. (Reporting by Jorge Otaola and Walter Bianchi; Writing by Hilary Burke; Editing by Diane Craft)