By Alexia Vlahos

SANTIAGO, June 18 (Reuters) - Chile's leading share index firmed on Thursday, rising with commodity stocks a day after its biggest one-day percentage fall since December, while the peso ended at another near 9-month high, traders said.

The blue-chip IPSA index .IPSA was 0.84 percent firmer at 3,132 while the all-market IGPA index .IGPA rose 0.66 percent to 14,961.

"There is a small bounce in (steelmaker) CAP which had one of the biggest falls yesterday," Roberto Guzman, head of investment at the FIT Research brokerage. "Retail shares are also seeing more demand."

Resource-based stocks rebounded on Thursday after a sharp fall on Wednesday due to profit-taking following recent gains.

The IPSA, which is up 32 percent year-to-date, rose around 16 percent in May, when it posted its biggest gain in a single month since January 1994.

Last week the Chilean bourse hit its highest levels since December 2007.

Shares in Steelmaker CAP CAP.SN rose 3.17 percent to 13,555 pesos after sinking more than 5 percent the day before.

Soquimich SQM_pb.SN, Chile's leading exporter of fertilizer and one of the world's biggest producers of iodine and lithium, rose 1.32 percent to 19,501 pesos after it plunged over 6 percent on Wednesday.