RE:C Series prefs. are dirt cheap C Series Preferreds are perpetual - coupon rate is fixed at 5.75% (based on par).
If interst rates move up, these types of preferreds drop in price.
Company credit rating also plays a large part.
Another important factor is the perceived likelihood of Innergex redeeming the shares.
These shares can't be redeemed until January 2018 (at $26, $25.75 in 2019, ...., $25 in 2022 or later).
These shares were under $19 a year ago (yield over 7.5%), probably due in part to tax loss selling.
Lack of liquidity (often less than 3000 shares per day) can cause some volatility.
With no likelihood of redemption for seven years, the share price will fluctuate based on interest rates and Innergex's performance.