direi che si
si tratta del valore di carico cui si fa riferimento per calcolare il capital gain

in termini contabili si parla solitamente di valore di carico
ma per un estate in generale secondo me anche "base fiscale" può funzionare

allego un po' di riferimenti:
http://rayfd.me/2012/11/04/private-wealth-management-low-bas...

http://www.osbar.org/!newsletters/814/2009/Est_2009Apr.pdf

.."Gifts of Depreciated Stock. Usually, we’re reluctant to advise our clients to make in-kind gifts of stock due to the adverse income consequences associated with such gifts. In today’s market, however, it is not unusual for a client’s portfolio to be composed mostly of depreciated stock. Consider advising clients to make in-kind gifts of depreciated stock to younger generations. For donees of depreciated stock, gains are calculated based on the donor’s original basis, while losses are only allowed to the extent that the loss occurred after the donee acquired the asset. So if Grandma bought her Google stock at $500 per share and it’s now worth $350 per share, gifting the stock to her grandchildren means that the grandchildren won’t recognize any gain unless the stock is sold above $500 per share. If, however, a grandchild sells the stock at $340, the grandchild’s loss is only $10 per share. Obviously Grandma could sell the stock now, take the losses herself, and then gift the cash to her grandchildren, but gifting the stock gives the grandchildren a chance to earn more in the long run and encourages them to hold on to long-term investments."

http://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=...

...."La deducibilità delle perdite della partnership in capo
al socio non può eccedere il valore della basis della sua
quota di partecipazione nella partnership. Bisogna ricordare,
tuttavia, che la base fiscale comprende anche
- per la quota attribuibile al socio - le passività della
partnership (incluse quelle senza regresso)..."