Why are per-share market values called “shadow prices”?
The term “shadow price” has been used for many years to reflect the fact that a money market fund’s per-share value, when calculated on a current market basis, must and typically does very closely “shadow” or track the fund’s per-share value calculated using the amortized cost method. The SEC introduced the term in its regulations in 1996, but per-share market values have been called shadow prices since the early 1980s.
