A form of index-linked National Savings certificate, originally available only to pensioners.
〈英，非正式〉老奶奶公债（与物价指数挂钩的国民储蓄证券，原先只出售给领退休金的人）
Example sentencesExamples
I know for a fact my mother once had something I think was called a "granny bond" which was effectively a financial product offered to people above a certain age which had a slightly higher interest rate than people below could get.
The Government can also think of granny bonds for future pensioners and the bearer bonds.
There is no truth in the rumour that he has decided to go one better and start handing out ‘granny bonds’.