Barely two days after reporting a strong quarter, Qihoo 360 (UNKNOWN:QIHU.DL) is making a move to expand its capital base. The company announced it will float a new convertible senior notes offering. The issue will total $550 million in principal amount, with the notes maturing on Sept. 15, 2018, "subject to market conditions and other factors." The Chinese company also anticipates it will grant the initial purchasers of the notes a 30-day option to buy an additional $50 million in principal amount to cover over-allotments, if any.

The notes are to be convertible into Qihoo 360's American depositary shares, with two ADSes representing three class A shares of the company. The company said the conversion rate and other terms have not yet been completed; they are to be set when the offering is priced.

Qihoo 360 said it intends to use the proceeds of the issue "for general corporate purposes."

Currently, Qihoo 360 has nearly 118.7 million ADSes outstanding, which most recently closed at $79.26 apiece.