1099-b with no cost basis

[El2]

hello, 

thank you if guide me how to file.  tax payer have a 1099-B with zero cost basis and  sale price is $ 23000, also tax payer have a separate  W2 box12 with code V for 26000, should i put the V amount on cost basis?

[Just-Lisa-Now-]

yes, assuming everything that was included on the W2 as Code V was all sold

[BobKamman]

But is that a reasonable assumption?  A $3,000 loss in a short time?  Or did he keep some of the shares?