Special - Financial definition
Concise definition of the term special
If there is a temporarily limited supply of a particular security it is said to be 'on special'. The repo rate for the security will decrease (because there is a short supply of the security relative to demand), the bond becomes more expensive to buy and its yield will tend to fall as the bond becomes expensive.
Comprehensive definition of the term special
A condition of limited supply may be referred to as a short squeeze (particularly in a basis trade) as those who are short the bond find it difficult (and expensive) to buy the issue.