Both men most recently worked on the precious metals desk at Scotiabank, Down for 13 years and Penney for two years as head of the PGMs trading.
Down has over 25 years of industry experience, and prior to Scotiabank worked at Mitsui and Mitsubishi.
During Penney's 13 years in commodities, he has also been a director at Standard Chartered Bank and a precious metals trader at Mitsui and Natixis.
Having joined in August, a month before Down, Penney is overseeing RBC's global PGMs trading books.
RBC said the two new directors would assist in expanding the bank's precious metals business in Europe across the petrochemical, refining, automotive and electronic sectors.