From their press release: “The Office of Federal Housing Enterprise Oversight (OFHEO) has finalized for publication in the Federal Register a regulation requiring Fannie Mae and Freddie Mac (the “Enterprises”) to report mortgage fraud or possible mortgage fraud in a timely fashion.” OFHEO is the regulatory oversight agency for GSE’s (Government Sponsored Enterprises) like Fannie Mae and Freddie Mac.
Complete text of the final regulation can be found here. [note: pdf] 
Appraisal fraud is now considered within the definition of mortgage fraud. This rightfully defines those who pressure appraisers to reach a specific value or they won’t receive future business as committing a fraudulent act.
Excerpt… Â§ 1731.2 Definitions.
(c) Mortgage fraud means a material misstatement, misrepresentation, or omission relied upon by an Enterprise to fund or purchase — or >not to fund or purchase — a mortgage, including a mortgage associated with a mortgage-backed security or similar financial instrument >issued or guaranteed by an Enterprise. Such mortgage fraud includes, but is not limited to, a material misstatement, misrepresentation, >or omission in identification and employment documents, mortgagee or mortgagor identity, and appraisals that are fraudulent.