Frank Quattrone, the controversial financier who rose to prominence during Silicon Valley’s boom years before becoming embroiled in federal obstruction of justice charges, on Tuesday announced his long-awaited return to finance with the formation of a new advisory boutique.

In a sign of the depth of his personal contacts and continued star power in the technology capital, Quattrone’s re-emergence was accompanied by testimonials from some of the Valley’s leading lights, including Eric Schmidt, chief executive officer of Google, and Jim Breyer, a venture capitalist behind Facebook.