Credit Suisse First Boston (CSFB) is facing a possible criminal investigation into conflicts of interest in its research division, after Massachusetts regulators backed action by New York State against the bank.

The State of Massachusetts has been looking into whether CSFB analysts hyped up companies publicly that they privately had negative opinions on. Michael Nestor, chief securities regulator for the State of Massachusetts wrote on Thursday to Eliot Spitzer, New York State Attorney general, backing criminal proceedings.