BUENOS AIRES, March 16 (Reuters) - Argentina's stock, currency and bond market trends on Monday.
* MerVal stocks index .MERV tracked Wall Street and Brazil's market lower, slipping 0.91 percent to 1,033.79 points after hitting a three-week high on Friday.
* Shares in bellwether Tenaris TENA.BA, which makes steel pipes for the energy industry, ended down 0.87 percent at 34.15 pesos, after rising by as much as 1.6 percent earlier in the day.
* On the broad market volume was modest at $10.6 million, with Tenaris trading accounting for more than 40 percent of that. Of active issues 37 advanced, 13 declined and 15 were unchanged.
* Argentine bonds dipped 0.5 percent on average in local over-the-counter trade, as investors reacted warily to the government's surprise announcement on Friday that it will press to move mid-term elections up by four months, purportedly to focus energy on the impact of the global economic slide.
* The move was seen as fresh evidence of the government's unpredictable behavior, and was viewed by many as a political ploy to try to improve the ruling party's election prospects.
* The peso-denominated Boden 2012 bond ARBODEN12=RASL shed 1.5 percent, according to the ask price.
* In formal exchange between banks, the peso firmed by 0.21 percent to 3.64/3.6425 per dollar ARS=RASL, with the central bank intervening to keep the local currency from depreciating further after weeks of losses.
* The central bank pursues a managed float policy on the foreign exchange market and has allowed the peso to slowly lose value so that Argentine exports can remain competitive, but it injects dollars into the market most days to keep it from sliding too fast. The peso has lost more than 5 percent of its value against the dollar since the start of the year.
* In informal trade between foreign exchange houses, as measured by Reuters, the peso slumped 0.20 percent to 3.7375/3.7425 ARSB=. (Reporting by Walter Bianchi; Writing by Hilary Burke; Editing by Leslie Adler)