Twitter taps the debt markets, announces convertible bond offering. Friday morning Twitter TWTR -1.01% said it raised $1.8 billion in the convertible bond offering it announced earlier in the week, up from the $1.3 billion it planned to raise as the deal met with robust demand. The five-year tranche of the offering, with notes due in 2019, carried a 0.25% interest rate, while the seven-year 2021 notes bear 1% interest, payable semi-annually ...