Reconstruction:Proto-Finnic/-ttu

Etymology
The passive marker followed by  or possibly  (see below)

Reconstruction
Many descendants point to *-(t)tut. The final *-t has usually been considered to be by analogy with the active participle ending. However some Ostrobothnian dialects have participle forms such as otettuen. If from earlier *otettuden, this could be evidence for *-(t)tut being the original form. It could then be akin to the end of (and possibly be the same as the adjectival suffix )

Suffix

 * 1) (having been) -ed;