Curious about recent 1909 VDB price increases

Higashiyama

I've noticed that very high end (MS67 RD) 1909 VDBs have seen a major increase in price over the past year. It is true for both grading services, but seems especially true of PCGS coins.

Is this a registry phenomenon, or is something else happening?

cladking

It might indicate increasing numbers of type collectors. The '09-VDB circs
have been strong for several years. Maybe the returning baby boomers
are upgrading now.

TWQG

Ditto cladking on the type collectors.
That one in 66 has about doubled in the last three years.

edit to add that it is a one year type with the VDB on the reverse and the S mint is too expensive an alternative.
Interestingly, the scarcer 09 no vdb in 66 is about the same price because it's not chased by type collectors.