Praise be to Allah.
It is permissible to engage in trade during the Hajj season. Al-Tabari narrated in his Tafseer with his isnaad that Ibn ‘Abbaas (may Allaah be pleased with him) said concerning the verse (interpretation of the meaning), “There is no sin on you if you seek the Bounty of your Lord (during pilgrimage by trading)” [al-Baqarah 2:198]:
There is no sin on you if you buy and sell before and after ihraam.
And Allaah is the Source of strength.