This is despite his suspension by Rivers branch and removal by the NWC, by giving effect to his resignation in 2018.
Apart from informing INEC that he is the acting chairman, Giadom has set up an account on Twitter.
His bio page describes him as acting national chairman.
However, the account is yet to have any traction: he has just 150 followers.
Giadom has now summoned an emergency National Executive Council meeting of the party for Thursday 25 June.
According to a notification letter that he sent to INEC today, the meeting will take place at 10am at the Presidential Villa, Abuja.
But in another notice to APC NEC members, the meeting will take place at noon, same venue.
Unless there is a denunciation of the meeting by President Muhammadu Buhari, it implies he is backing Giadom, against other members of the NWC.
Buhari is yet to speak publicly over the leadership tussle, following the suspension of Adams Oshiomhole as the chairman of the party by the courts.
On Monday, Buhari met with three governors, Atiku Bagudu of Kebbi, Simon Lalong of Plateau and Mohammed Abubakar Badaru of Jigawa.
At least one of the governors backs Giadom.
Majority members of the NWC have named Abiola Ajimobi, the party’s deputy chairman as the acting chairman.
But because Ajimobi is indisposed, critically ill at a Lagos hospital, his role is being performed by Hilliard Etta, the vice chairman.
On Tuesday, the police sealed the national headquarters of the party, at the instruction of the Inspector General of Police Mohammed Adamu.
His aim was to seek a truce between the warring groups.
It was not clear how the top policeman resolved the political conflict.
But by Monday evening, the police opened the APC office, all over again.
Giadom’s letter to INEC: