Transocean shares plunge after unveiling $125 million stock offering

** U.S.-listed shares of offshore drill services firm Transocean RIG fall 13.7% to $3.14 premarket

** Co announces pricing of a public offering for 125 million shares at $3.05 per share, implying a more than 16% discount to co's last close

** Offering size increases from the originally proposed 100 million shares

** RIG expects to raise $381.3 million from the offering before deducting commisions and expenses

** Citigroup, Morgan Stanley, DNB Carnegie, Goldman Sachs & Co. LLC and Wells Fargo Securities are joint book-runners for offering

** Proceeds to be used to repay or redeem debt, including a portion of the 8.00% Senior Notes due February 2027 issued by co

** Underwriters have a 30-day option to purchase an additional 18.8 million shares at the offering price

** With 943.1 million shares outstanding, co has a current market cap of $3.43 bln - according to data compiled by LSEG

** Up to last close, stock down nearly 3% YTD