Kostantinos focuses his practice on corporate and securities law and capital markets transactions. He advises public and private companies, underwriters, and financial institutions on a broad range of securities matters, including initial public offerings, PIPE transactions, registered direct offerings, and other registered and unregistered securities offerings.

In addition to his transactional work, Kostantinos regularly counsels public company clients on ongoing Exchange Act reporting and disclosure obligations, including periodic reports on Forms 10-K and 10-Q, current reports on Form 8-K, and proxy statement preparation. He also advises boards of directors and management teams on corporate governance matters and stock exchange requirements, helping clients navigate evolving regulatory expectations and best practices.

Prior to joining Mintz, Kostantinos was an associate and summer associate at a New York–based international law firm, where he worked on various aspects of financings and capital market transactions.

While attending law school, Kostantinos served as a judicial intern for the Honorable Jack B. Weinstein of the US District Court for the Eastern District of New York. In law school, Kostantinos served on the Fordham Urban Law Journal and as interschool competitions editor for the Fordham Moot Court Board. He was also the student representative to the Fordham Law Long Range Planning Committee.