The new commissioners will be senior civil servants and will be appointed to lead DIT operations such as export promotion, inward and outward investment and overseas trade policy.
The appointments are expected to be confirmed within the first half of 2018.
The commissioners will operate across nine geographical areas: Africa, Asia-Pacific, China, Eastern Europe and Central Asian Network, Europe, Latin America, Middle East, North America and South America.
HMTCs were a manifesto pledge by the government, and it is hoped they will offer some level of stability in the upcoming uncertain period for trade.
In August, the DIT appointed a chief trade negotiations expert, Crawford Falconer, from New Zealand to lead trade negotiations with other countries in the run-up to Brexit.