N indicates the total number of observations, Mean represents the mean duration values of green sukuk and green bonds and Diff. denotes the difference in mean duration values between green sukuk and green bonds. The t-values represent the ratio of the difference between the paired observations to the standard error of the difference. The p-value indicates the probability that the observed differences occurred by chance, with significance levels denoted as *p < 0.10, **p < 0.05 and ***p < 0.01