It's a control symbol. They come with letters at least A thru X (at least), which can find sorted in Richard Schaefer's notebooks (published by ANS), Binder 19, pp. 91-107. "V's" are on pages 106-7. At a glance, I didn't notice your specimen, but worth double-checking: http://numismatics.org/archives/ark:/53695/schaefer.rrdp.processed_300-399 https://numismatics.org/authority/schaefer_richard One of mine is a Brockage, so it appears in a different one of his binders (twice!) (Binder 22):
@Curtis I was unable to find any L Thorius Balbus coins in those pages. I did find that my coin is an EX Goodman example. But also unable to find it in the sale.
It's the first link I gave (processed notebook 19 for Crawford 300 to 399, since this type is 316/1): http://numismatics.org/archives/ark:/53695/schaefer.rrdp.processed_300-399 There are 17 pages in a row with different marks in order alphabetically, which is presumably the sequence in which they were struck. The 106th page of the document sows control marks T & V. The 107th page is V & X. (Numbered & titled at the bottom of each frame.) For whatever reason, 316/1 is not linked/labeled in the list of specific Crawford numbers below so you have to scroll right using the labels under the images. (They're in order by Crawford number, from 300-399, and sequentially and/or alphabetically within each number.) I'll upload the images/links in a moment / check back... EDIT: @Pickin and Grinin -- they don't seem to let you link/download specific pages/images, but here's a screenshot of the first page (106) that includes the V's (see also the following, p. 107):
@Curtis I will look thru again later the closest I could find was the Toderi example. It still has some differences. There is a huge die break on the bulls hind quarter and a die crack the runs down thru the HO of Thorius.
If we're still talking about this Thorius Balbus with V control on the reverse there are 32 of them visible in just the screenshot in my last comment. There are more in the linked document Edit: I see now, I think an exact die-match is the goal, which may not be possible in this case