Shares of Bill.com Holdings Inc. /zigman2/quotes/215406166/composite BILL -0.54% dropped 5.6% in premarket trading Tuesday, after the provider of software aimed at simplifying back-office operations announced the offering of $1 billion worth of common stock to the public and $500 million in convertible debt to qualified institutional investors. The debt, which are senior notes due 2027, can be converted into common stock, cash or a combination of both, at the election of the company. For the common stock offering, which represents about 3.7% of Bill.com's market capitalization of $26.9 billion as of Monday's close, the company plans to use the proceeds for general corporate purposes, which could include potential acquisitions. Bill.com's stock has soared 56.6% over the past three months through Monday, and closed at a record $297.14 on Sept. 3. In comparison, the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.11% has gained 3.2% the past three months, and closed at a record on Sept. 2.