A top connector (12) for a tether (16) of a subsea buoy (10) comprises a support (46), a lever member (60) movable about a pivot axis, and a chain stop mechanism (64) mounted on the lever member (60) to be situated below the pivot axis in use. The lever member (60) is pivotably connected to the support (46) via a flex joint (58) arranged to bear a tensile load exerted by a top chain (22) of the tether (16) when engaged with the chain stop mechanism (64). The flex joint (58) improves bending fatigue life of the top chain (22). A frame (30) extends upwardly from the support (46) to carry a sheave (32) for the top chain (22). A pivotably connected lever member (62) extends downwardly from the support (46). The lever member (62) is pivotable relative to the support (46) and the frame (30), allowing a compact arrangement that avoids the frame (30), the top chain (22) or the sheave (32) clashing with the shell (14) of the buoy (10).