Security that is tradeable but originally posed no cost to the seller. For example, a renounceable right being sold by the original owner to another investor is considered nil-paid. A right is an opportunity to purchase more shares, usually at discount, given to shareholders by a corporation. The shareholders receive these rights at no cost, and if the rights are renounceable, the shareholders can choose to sell them on the market.
Taobiz explains Nil-Paid
Though the word "nil-paid" may suggest that nil-paid rights give shareholders the right to acquire new shares for no cost, this is not the case. Nil-paid rights are only the right to acquire more shares at the current share price or a discount. The corporation issuing the rights to its shareholders does not receive payment for the rights, but if the shareholders decide to exercise the rights, they must pay for the securities they are given the right to buy.