The Globe and Mail reports in its Friday, April 25, edition that RBC Dominion Securities analyst Nathan Piper has downgraded Pacific Rubiales Energy ($17.87) to "sector perform" from "outperform." The Globe's Darcy Keith, Tim Shufelt and Jody White write in the Eye On Equities column that Mr. Piper cut his price target to $21 from $23. The analyst warns that a big increase in operating costs could erode investor sentiment toward Pacific Rubiales Energy. Pacific Rubiales shares have advanced by almost 40 per cent in two months. Mr. Piper lowered his rating after the company, which is the largest private oil producer in Columbia, reported an increase in first quarter operating expenses of up to 25 per cent from the previous quarter. Mr. Piper says, "Although production guidance for FY14 remains unchanged we think the cost increase could impact recent positive investor sentiment." Credit Suisse also dropped its price target to $17 from $18 and reiterated a "neutral" rating. The average analyst price target, according to Bloomberg, is $24.28. Credit Suisse analyst David Phung downgraded Pacific Rubiales to "neutral" from "outperform" in the Eye column on Oct. 16, 2013. The shares were then worth $22.52.