Cipher Digital slides on proposed $850 mln convertible notes offering

** Cipher Digital CIFR.O shares slide 12.46% to $11.38 premarket

** The AI data center operator announces proposed private offering of convertible senior notes worth $850 mln, due 2032

** Notes carry a 0% coupon, meaning CIFR will pay no regular interest on the debt

** Initial purchasers have a 13-day option to buy up to an additional $150 mln in notes - CIFR

** Says proceeds to fund capped call transactions, Barber Lake project investment, HPC expansion and general corporate purposes

** Capped call transactions aim to reduce potential shareholder dilution when the new notes convert into shares, subject to a cap

** As of last close CIFR down 11.92% YTD