A popular bond, but note the numerator - it is preceded by a capital letter N.
This is the rarest version of the 1920 "millionaires".
The variety is not included in J. Mazur's Catalog (and in Supplement No. 1 to this Catalog). Probably it will be included in the next Supplement as variety "d". A millipede with this type of numerator is also not included on the starepapiery.com blog, where all other popular varieties of this bond are presented in a study of debt securities.
The numerator preceded by the letter N was first presented on the SKHPW group in April 2023. This numerator appears with the lowest bond numbers in the range from 1 to about 9000 (this auction features the third piece recorded to date, after N0004524 and N0008115).
Highly recommended!
