Citigroup

(C) - Get Report

filed with the

Securities and Exchange Commission

to offer up to $20.5 billion in debt securities, common and preferred stock, warrants and depositary shares.

The financial services firm is also offering an additional $4.5 billion in previously registered but unsold securities.

Citigroup said it will use the proceeds from the offering for general corporate purposes, mainly to fund its operating units. The company may also use some of the proceeds to finance possible acquisitions or business expansion and to refinance or extend the maturity of existing debt obligations.