“US accounting and banking regulations will not require that loan portfolios held in the "banking book" be marked to market before 2024.”

Although marking to market provides greater transparency to all bank stakeholders (shareholders, depositors, creditors) who have a legitimate desire to more fully understand the economics of a bank's business, the result would be a significant increase in earnings volatility. Increased volatility would make it more difficult for banks to play a stabilizing role in the economy and may make it more difficult for them to obtain stable access to capital.

In addition, marking to market actually involves large conceptual and technological challenges. Overcoming these would require significant investment in technology and cultuaral change.

As a result, banks will resist marking their loan portfolios to market for at least another 20 years.