One of the main reasons that the 1921-D does not get the attention it deserves is that while low mintage at 208,000 pieces, it was joined that year by the Philadelphia 1921 Walking Liberty half dollar which had a mintage of 246,000. It hurt the recognition of the 1921-D as it did not seem as special as it should have.
There was a good reason for the low mintage of the 1921-D. The economy was hurting badly as the World War I boom times ended. Unemployment soared. Coin demand plunged. Fewer halves were produced.
The 1921-D is the key Walking Liberty half dollar in circulated grades. Today, it lists for $295 in G-4 and that price puts it above the similar mintage 1921 which is at $150 with very few other Walking Liberty half dollars above $50 in G-4.
The circulated prices are inexpensive when you consider the mintage of the 1921-D, 1921 and others. There were significant numbers of all dates that circulated until being plucked from circulation by collectors. That was a slow process. Even into the 1940s, there were still many Barber half dollars in circulation and few half dollar collectors to change the situation. Until the Barber half dollar dates disappeared, not many were saving the 1921-D Walking Liberty coins for their collection.
By the time people did start to take notice of the Walking Liberty half dollar it was probably at least the late 1930s when the first holders for complete sets became available. Even then, the half dollar would have to wait as the denomination was too expensive even at face value for many to collect. By the time people did pull the 1921-D from circulation, many were in very low grades.
The situation with Mint State examples also is complicated as the average collector in 1921 was confronted with a range of options and most of them were expensive. There were low mintage dates for virtually every denomination so the half dollar was just one of many possibilities along with new silver dollars and commemoratives.
Low mintages today did not appear that low back in 1921 as in 1913 to 1915, Philadelphia produced half dollars that had lower mintages than the 1921-D. Half dollar totals under 1 million were routine and while the 1921-D was low, it was not likely to create hoarding. As a result, we find the 1921-D is not available in any numbers in Mint State with a price of $13,500 in MS-60 while an MS-65 is $33,500.
The MS-60 price of the 1921-D is topped by only the 1921-S, which, ironically, despite a higher mintage, appears to have barely been saved at all when they were released. The 1921-S, as well as the 1918-D, would also have higher MS-65 prices than the 1921-D.
Despite being lower than a few other dates in price in Mint State, the 1921-D is far from common. At NGC, they report grading just 18 examples of the 1921-D in MS-65 and three in MS-66 out of a total of 170 called Mint State. At PCGS, the total in MS-65 is 32 with three more in MS-66 out of just 241 examples called Mint State.
The 1921-D will remain very much in demand in all grades.