Owen Bertram said: "Much thanks, my Lord. However, this time... these impoverished brothers have worked very hard, I can't shortchange them, so I really can't give away too much of your share."
Under Owen's constant misdirection, Nick Liam naturally assumed that it was because of the near hundred impoverished Cultivators in the Zombie Cave that Owen could outmanoeuvre the high-level Spirit Insects, causing Evans Graham's gains to shrink greatly.
After all, stating that all the Spirit Insects were captured single-handedly by Owen would raise eyebrows, so Nick Liam never even considered that possibility.
Although this secret will eventually be revealed, by then, Owen most likely would have completed his trade with the Fifth Prince, or even ended the Dragon and Snake List, and escaped back to the Summit Metropolitan Office!
Even if Nick Liam were to interrogate him then, Owen had his excuse: I never told you that they helped me capture them; it was all your own misunderstanding.