After taking over most of Colonial Bank ( CNB ) on Friday, BB&T Corp. ( BBT ) said Monday it has commenced a public offering of $750 million of common stock, saying the proceeds, which will qualify as tangible common equity and Tier 1 regulatory capital, will be used for general corporate purposes. The southeast regional bank also said the underwriters in the offering will have a 30-day option to purchase up to an additional 15 percent of the offered amount of common stock from the company to cover over-allotments, if any. Credit Suisse ( CS ) and Deutsche Bank ( DB ) are the joint book runners.