Radiant Systems, which markets POS systems, has filed a $150 million shelf offering with the SEC. Of that amount, $135 million will be offering by the company and the rest by selling shareholders. The company said that proceeds would be used for general corporate purposes, including acquisitions of companies or related technologies. A shelf offering can be used at any time, which suggests it's ideal for acquisitions which could close at any time and which might involves securities as part of the purchase.  The offering may include common stock, preferred stock, and warrants to purchase common or preferred stock in any combination up to the amount stated in the documents filed with the SEC. A prospectus, which is not yet available, should provide more detail.