Such appointments are rare in the ultra-conservative kingdom where women face multi-layered restrictions, including not mixing with men at the workplace.
Suhaimi has an impressive resume.
She joins NCB from Jadwa Investment, where she was head of asset management, responsible for assets exceeding 17 billion riyals (USD 4.53 billion), NCB Capital said in a statement.
She was earlier head of portfolio management at Jadwa, which she joined in 2007 after five years in a senior position at Samba Financial Group.
Saudi Arabia imposes a strict interpretation of Islamic law, forbidding women to work or travel without authorisation from their male guardians.
It is also the only country to ban women from driving, and a woman cannot obtain an identification card without the consent of her guardian.