This is referred to as liquidity premium (the former) or discount (the latter). (cnbc.com)
How profitable is automated multi-horizon extraction of liquidity premiums in currency exchange markets? (cxoadvisory.com)
If the replacement bond is going to be a Treasury, choose the off - the - run rather than the on - the - run so that you're not paying for liquidity premium, which is additional richness priced into the on - the - runs due to the demand by the repo markets. (indexologyblog.com)