PPP co-chairman Asif Zardari has also been asked to appear before the anti-corruption body.
Sources said Bilawal is a shareholder in a company, Park Enclave.
Bilawal is unlikely to appear and will instead be represented by his legal counsel Farooq H Naek, sources added.
Senior PPP leader and former senator Farhatullah Babar, confirming the news, termed the step as part of NAB’s political agenda.
NAB summons Chairman BBZ on 13th in case of a company set up when he was less than a year old and a minority shareholder. Ratcheting up to pressure Party leadership. Thank you NAB; the more you do the more you expose yourself as political arm of govt for witch hunt.
— Farhatullah Babar (@FarhatullahB) December 9, 2018
Such steps only go to expose NAB’s political objectives, he said.
Babar added that the cases in which Bilawal has been summoned are in the timeline when the PPP chairman was merely a year old.
Bilawal was also sent a “tough” questionnaire early this week by a joint investigation team in a fake accounts case, in which his father, Zardari, and aunt, Faryal Talpur, have also appeared several times.