The subject of the paper is the problematic sequence prosvěštaesi in Ps. 75:5 of the eleventh-century Novgorod Psalter written on the wax plates (cerae). This sequence has generally been thought to be a corrupted present-tense form of the verb prosvěštati. The author, however, argues that the sequence in question represents a participle construction prosvěštaję esi, written without jotation and consequently with assimilation and contraction of vowels in the final part of the participle. Some rare parallels to this abnormal form found in Slavic mss illustrate the author’s interpretation. As this fragment is relevant for textology of Ps. 75:5 the interpretation could be of interest for the further investigation of the origin of the Novgorod Psalter.