BUENOS AIRES, May 19 (Reuters) - Argentina's stock, currency and bond market trends on Tuesday.
* The MerVal stocks index .MERV rose 0.31 percent to 1,533.39 points, with selective profit-taking in the banking and service sectors trimming gains late in the session.
* The index is up 20.2 percent since May 1.
* MerVal heavyweight Tenaris (TENA.BA), which makes steel tubes for the global energy industry, inched 0.56 percent higher to 54 pesos a share.
* On the broad stock market, volume was moderate at $20.3 million. Of active issues, 49 advanced, 24 declined and 8 were unchanged.
* Prices for government bonds traded over-the-counter in Buenos Aires rose 0.7 percent on average, accumulating gains of 12.5 percent since the start of the month.
* The dollar-denominated 2017 Bonar X bond ARBONAR17D=RASL rose 2.05 percent to an ask price of 44.90.
* Local media and market players are once again discussing the possibility that the government could try to extend maturities on its Boden 2012 paper ARBODEN12=RASL ARBODEN12D=RASL, drawing in investors by offering to pre-pay obligations that come due in August.
* In formal exchange between banks, the Argentine peso closed 0.07 percent weaker at 3.7275/3.73 per dollar ARS=RASL, reacting to the central bank's dollar purchases on the market, traders said.
* In informal trade between foreign exchange houses, as measured by Reuters, the peso shed 0.53 percent to end at 3.785/3.79 ARSB=. (Reporting by Jorge Otaola; Writing by Hilary Burke; Editing by Dan Grebler)