A stock that cannot be transferred, especially because of improperly filed paperwork or another fairly innocuous reason. In other words, the delivery of a dirty stock is only stopped by legal and/or regulatory rules. See also: Good delivery.
A security that is not in deliverable form for transfer. For example, a certificate may not be endorsed properly.
It is our experience that during the entire period of Northern franchise, not only have passengers been promised new rolling stock, but those travelling from Slaithwaite and Marsden have had to suffer the most broken down, ruined, leaking and dirty stock in the country.