(Updates with closing prices)
BUENOS AIRES, Oct 8 (Reuters) - Argentine bonds and stocks fell on Wednesday as investors dumped riskier assets due to the global financial crisis, while the peso ended firmer as central bank dollar sales managed to reverse its downward trend.
The MerVal index of leading shares .MERV closed down 1.82 percent at 1,359.27, its fifth consecutive session of losses.
"In Buenos Aires, we're seeing prices that reflect investor panic and not the true value of the companies," said Francisco Marra, a trader at Bull Markets Brokers.
Index heavyweight Tenaris (TENA.BA), the world's top producer of seamless steel tubes for the energy industry, dragged down the MerVal with a loss of 1.81 percent to 46 pesos per share.
Volume on the broad market was a moderate $36 million.
The peso ended firmer against the dollar as central bank sales of dollars helped reverse the market trend. For most of the session, the peso weakened as local savers and companies opted for safe-haven dollars.
In informal trade between foreign exchange houses, as measured by Reuters, the peso firmed 0.61 percent to end at 3.29/3.30 per U.S. dollar ARSB= after dipping to 3.42 per dollar earlier in the session.
The peso had weakened for the four previous sessions, shedding 2.39 percent on Tuesday.
In formal trade between banks ARS=RASL the peso weakened 0.16 percent to end at 3.22/3.2225 per dollar. The central bank intervenes in the interbank market to avoid abrupt movements in the value of the peso.
Argentine bonds fell 5 percent on average in over-the-counter trade due to a fresh bout of selling riskier emerging-market assets, extending the average 2 percent loss racked up in the prior session.
Peso-denominated Par bonds were among the hardest hit, sliding 7.9 percent according to the ask price.
Argentina's debt spread over similar U.S. Treasuries widened 39 basis points to 1,271 on the JPMorgan Emerging Markets Bond Index Plus (EMBI+) 11EMJ. (Reporting by Walter Bianchi; Writing by Helen Popper; Editing by James Dalgleish)