Chile shares post biggest monthly gain in 15 yrs

(Updates with bourse close)

By Alexia Vlahos

SANTIAGO, May 29 (Reuters) - Chilean stocks closed mixed on Friday but blue-chip stocks posted their biggest monthly gain in 15 years, traders said, while the peso closed firmer.

The blue-chip IPSA index .IPSA closed 0.05 percent weaker at 3,100.42 points, preliminary closing data showed, giving up intra-day gains in late trade. The all-market IGPA index .IGPA rose 0.54 percent to 14,684.06 points.

The IPSA, which is up 30.5 percent year-to-date, rose around 16 percent in May, its biggest gain in a single month since January 1994.

Chile's bourse has risen sharply in the past few weeks, led by sectors such as construction, retail and commodities.

"The electrical companies have risen a lot and that is the sector that has pushed the market today," said Felipe Cruz, a trader at the CorpCapital brokerage.

Shares in industrial conglomerate Copec COP.SN, the most heavily weighted company on the bourse, rose 1.36 percent to 7,091.90 pesos a share.

Regional energy group Enersis (ENE.SN) rose 2.27 percent to 190.29 pesos a share, while electricity generator Endesa Chile END.SN rose 0.64 percent to 824.89 pesos. Power generator AES Gener CHG.SN rose 2.24 percent to 255.57 pesos.

Retailers also posted strong gains.

Shares of Cencosud CEN.SN, one of Latin America's largest retailers, rose 2.01 percent to 1,463.60 pesos a share, while fellow retail chain Ripley RIP.SN rose 5.54 percent to 417.07 pesos a share.

Shares in retail chain La Polar LAP.SN fell 0.86 percent to 1,928.80 pesos, after surging more than 15 percent on Thursday on an offer to merge with a supermarket affiliate of private equity fund Southern Cross Latin America.

The Chilean peso CLP=CL closed 0.5 percent firmer at 561.00/561.50 per dollar compared with Thursday's close of 563.80/564.10.

"The weakness of the dollar in foreign markets against other important currencies, namely the Euro, is favoring the peso," said one currency dealer.

The peso is up 14.3 percent against the dollar year-to-date after slumping 22.3 percent in 2008. (Additional reporting by Froilan Romero and Manuel Farias. Editing by Simon Gardner and Dan Grebler)