BG Chap 15 - The Supreme Person, Kṛṣṇa - higher than Paramātmā
Kṛṣṇa summarizes the meaning of the Vedas as defined by Vyasadeva by next explaining the being who is higher than the two kinds of beings and also the Paramātmā.
Kṛṣṇa is superior to both the conditioned and liberated jīvas. He is celebrated in the Vedas and the smṛtis (loka) as the Supreme Person (Puruṣottama). Loka means that which reveals the meaning of the Vedas and thus refers to smṛti. No one can surpass the Supreme Personality of Godhead, Kṛṣṇa—neither the conditioned soul nor the liberated soul. He is therefore the greatest of personalities. The Supreme Personality is exhibiting and diffusing His spiritual effulgence, which is the ultimate illumination. That Supreme Personality also has a localized aspect as Paramātmā.
Viśvanātha Cakravartī explains that having spoken about the object of worship of the jṇānīs and yogīs, the Lord now speaks about the object of worship of the devotees, Bhagavān. Kṛṣṇa denotes the supreme excellence of His own svarūpa using the name Puruṣottama – He who is superior (uttama) to the Paramātmā (puruṣa). He is superior to the jīva (kṣaram), to Brahman (akṣaram), and also to the unchanging person, Paramātmā (puruṣa). The word ‘ca’ in ‘api cottamaḥ’ indicates that Kṛṣṇa is superior even to the Lord of Vaikuṇṭha.