Penn West Exploration Ltd. (previously known as Penn West Energy Trust) — still referred to as known as Penn West Petroleum in the media — was a prominent mid-sized Canadian oil and natural gas production company based in Calgary, Alberta. For a while it was one of the S&P/TSX 60, the sixty largest companies on the Toronto Stock Exchange. From 2005-2011 it was a Canadian royalty trust (CANROY), and as such did not pay federal income taxes. With a market capitalization in January 2008 of approximately US $9.5 billion, it was the largest oil and gas energy trust in North America.
"The resulting double-digit dividend yields grabbed dividend investors’ attention in the mid-2000s. Eventually the government cracked down and starting in 2011, trusts were required to pay the same taxes as regular corporations. Consequently, all trusts converted to corporations, and many cut their dividends."