It is one of the largest private funding organizations for biological and medical research in the United States. HHMI spends about $1 million per HHMI Investigator per year, which amounts to annual investment in biomedical research of about $825 million. The institute has an endowment of $18.2 billion, making it the second-wealthiest philanthropic organization in the United States and the second-best endowed medical research foundation in the world. HHMI is the former owner of the Hughes Aircraft Company - an American aerospace firm which was divested to various firms over time.
HHMI completed the building of a new research campus in Ashburn, Virginia called Janelia Research Campus in October 2006. It is modeled after AT&T's Bell Labs and the Medical Research Council's Laboratory of Molecular Biology. With a main laboratory building nearly 1,000 feet (300 m) long, it contains 760,000 square feet (71,000 m2) of enclosed space, used primarily for research. The campus also features apartments for visiting researchers.
In 2007, HHMI and the publisher Elsevier announced they have established an agreement to make author manuscripts of HHMI research articles published in Elsevier and Cell Press journals publicly available six months following final publication. The agreement takes effect for articles published after September 1, 2007. In 2008, the Trustees of the Howard Hughes Medical Institute selected Dr. Robert Tjian as the new president of HHMI. In 2009, HHMI awarded fifty researchers, as part of the HHMI Early Career Scientist Competition. In 2016, the HHMI Trustees selected Dr. Erin O'Shea, a previous Vice President and Chief Scientific Officer at the institute, the new president of HHMI.