BUENOS AIRES, Dec 9 (Reuters) - Argentina's peso currency strengthened against the dollar on Tuesday after 18 consecutive losing sessions, as exporters cashed in foreign earnings for pesos and as the central bank sold greenbacks.
Stocks and bonds also gained, catching up with Wall Street gains from a day earlier, when Argentina had a holiday.
The peso gained 1.24 percent to 3.4275/3.4325 per dollar ARS=RASL in formal interbank trade, after shedding more than 5 percent in a slump of almost four weeks. But traders said volume was low.
"The market really loosened up noticeably. The central bank contributed dollars as well as some exporters who influenced prices," said a trader.
Last week the peso hit new six-year lows, at its weakest level since 2002 when Argentina abandoned its currency peg and devalued the peso, as local investors and businesses sought the relative stability of dollars.
The peso also strengthened on Tuesday in trade between foreign exchange houses, as measured by Reuters. In that market the currency gained 0.21 percent to 3.4925/3.4975 per dollar ARSB=.
Meanwhile, the benchmark MerVal index .MERV gained for a fifth consecutive session, closing up 2.11 percent to 1,026.63 points, as local shares caught up with gains in their associated American Depositary Receipts on Monday when markets were closed in Argentina.
Volume on the broad market was light at $18 million and of active issues 39 advanced, 17 fell back and 9 closed unchanged.
Local shares in Brazilian oil company Petrobras (APBR.BA) led advances, soaring 13 percent to 35.5 pesos.
Petrobras ADRs PBR.N jumped 7.6 percent a day earlier in New York trade and they also jumped in Brazil (PETR4.SA).
Argentine sovereign bonds traded locally rose slightly in cautions trade. The dollar-denominated 2038 Par bond ARPARD=RASL, one of the most liquid issues, rose 2.1 percent to an ask price of 17.20.
Argentine debt prices have been severely damaged over concerns that government economic policy has left few options to refinance debt next year as the economy slows.
Reporting by Jorge Otaola and Walter Bianchi, writing by Fiona Ortiz; Editing by Diane Craft