Ātma-nikṣepa — The Total Deposit of the Self at Bhagavān's Feet
Ātma-nikṣepa is the act of prapatti itself — not a separately enumerated anga in Pillai Lokāchārya's five-anga Teṅkalai framework, but the overall act of self-surrender that encompasses the other angas. The compound means 'the depositing (nikṣepa) of the self/ātman (ātma)' — the jīva (individual soul) depositing itself entirely at Bhagavān's feet, surrendering all claim to independent selfhood, independent will, and independent ownership of its own ātman. This is the metaphysical core of Prapatti: the recognition and formal enactment of the ātman's fundamental ontological status as śeṣa (servant/dependent, that which exists entirely for another) to Bhagavān as śeṣī (the master, the one who owns all).
In Viśiṣṭādvaita Vedānta, the ātman does not merely behave as Bhagavān's property — it is Bhagavān's property, constitutively. The ātman's svarūpa (intrinsic nature) is śeṣatva: it exists for Bhagavān's purpose, its very being is a 'for-Bhagavān-ness.' Ātma-nikṣepa is the act of recognizing and enacting this ontological truth — the jīva stops pretending it has independent ownership of itself and surrenders the very pretense. The Āchāryas use the metaphor of depositing a treasure in a bank: when you deposit it, the treasure still exists and you may receive benefit from it — but you no longer carry the burden of guarding it yourself. Similarly, in Ātma-nikṣepa, the ātman is deposited at Bhagavān's feet, and Bhagavān becomes responsible for its protection, welfare, and ultimate liberation.
The Śrīvacana Bhūṣaṇam of Pillai Lokāchārya describes the irrevocability of Ātma-nikṣepa: once the ātman is deposited at Bhagavān's feet, it cannot be taken back. The surrender is complete and permanent. Maṇavāḷa Māmunigaḷ's commentary emphasizes that this is why Prapatti is a one-time act (sakṛt-kartavya) — unlike Bhakti-yoga which must be performed repeatedly across many lifetimes, Prapatti once performed cannot be undone. The ātma-nikṣepa has already occurred; the remaining life is simply the living-out of that surrender through kaiṅkarya.