mark to myth
n.— «Banking auditors are watching carefully to ensure bank valuations based on in-house mathematical models are not, in the phrase coined by Warren Buffett, “mark to myth.” In the backwash of the credit crisis, U.S. and European banks have revealed more than $50 billion of writedowns and losses from U.S. subprime mortgage loans, leveraged loan commitments and other assets since the end of August. Big chunks of those writedowns are based on mark-to-model valuations, which banks must justify to their auditors.» —“Auditors set to ensure banks don’t mark to myth” by Jane Baird in London Reuters Nov. 16, 2007. (source: Double-Tongued Dictionary)