- Manufacturing and marketing transformers, electrical equipment, electronic instruments, electrical materials and electrical machinery.

- Repairing and maintaining services for electrical equipment.

- Trade of restaurant and office for leasing.

- Other under business lience.

- 1963: Forerunner Transformer Manufacturing Factory that was establishedand;

- 1983: Insulated Material Workshop was separated to become Insulated Material Factory;

- 1994: Jointed with ABB Corporation to establish ABB Transformer Manufacturing Joint Stock Company;

- January 1999: Transformer Manufacturing Factory insulated and operated independently;

- 2003: Material Workshop was renamed to Ha Noi Electrical Equipment Joint Stock Company;

- March 2005: Transformer Manufacturing Factory renamed as Hanoi Transformer Manufacturing Joint Stock Company;

- September 2005: Hanoi Transformer Manufacturing and Electric Material JSC;, was established on the merger of Hanoi Electrical Equipment JSC and Hanoi Transformer Manufacturing JSC;

- 31 May 2007: Charter capital was raised up to VND30 billion;

- 27 December 2007: Became a public company;

- 06 December 2010: Listed on Hanoi Stock Exchange (HNX);

- 10 August 2011: Charter capital was raised up to VND35 billion;

- 07 May 2015: Delisted from Hanoi Stock Exchange (HNX);

- 27 September 2017: Traded on the UPCOM market;

- 19 July 2018: Charter capital was raised up to VND250 billion;