Energy Markets Improvement Act of 2005

Energy Markets Improvement Act of 2005 - Amends the Federal Power Act to require the Federal Energy Regulatory Commission (FERC) to promulgate regulations establishing an electronic information system to provide FERC and the public with access to information appropriate to facilitate price transparency and participation in markets subject to its jurisdiction.

Declares it shall be unlawful for any person or entity knowingly to: (1) enter into any contract or other arrangement to execute a round trip trade; or (2) use or employ, in connection with the purchase or sale of electric energy or transmission services subject to FERC jurisdiction, any manipulative or deceptive device or contrivance to affect the price, availability, or reliability of such electric energy or transmission services.

Authorizes revocation of the authority of a public utility to charge market-based rates if FERC finds that the utility has knowingly employed any manipulation, deception, or contrivance in violation of this Act.

Amends the Commodity Exchange Act to bring within its regulatory purview over-the-counter transactions in energy commodities, energy transactions, and electronic energy trading facilities.

Prohibits fraudulent transactions in connection with contracts of sale of any commodity for future delivery or certain other agreements, contracts, or transactions involving excluded or exempt commodities other than securities.

Subjects violations to civil and criminal penalties.