We used HST/WFC3 observations of a sample of 26 nearby ( \leq 20 pc ) mid to late T dwarfs to search for cooler companions and measure the multiplicity statistics of brown dwarfs .
Tightly-separated companions were searched for using a double-PSF fitting algorithm .
We also compared our detection limits based on simulations to other prior T5+ brown dwarf binary programs .
No new wide or tight companions were identified , which is consistent with the number of known T5+ binary systems and the resolution limits of WFC3 .
We use our results to add new constraints to the binary fraction of T - type brown dwarfs .
Modeling selection effects and adopting previously derived separation and mass ratio distributions , we find an upper limit total binary fraction of < 16 \% and < 25 \% assuming power law and flat mass ratio distributions respectively , which are consistent with previous results .
We also characterize a handful of targets around the L/T transition .