On April 3, Seattle's Dendreon Corp. said it had raised $46 million by selling 8 million shares and an additional 8 million warrants of its stock to an unnamed institutional investor.

The deal surprised the company's watchers, both because there was no indication that Dendreon needed to immediately raise the additional money and because of the deal's unusually favorable terms.

Today, two firms, Capital Ventures International and Heights Capital Management, said in a filing with the Securities and Exchange Commission that they had purchased 8 million shares of Dendreon's stock on April 3. See the filing here.

Heights Capital Management is Capital Ventures International's investment manager. The firm is a private equity arm of Susquehanna International Group, a financial institution that specializes in institutional sales and market making.

Heights Capital specializes in making so-called pipe investments, buying discounted stock from firms in need of capital. According to this Susquehanna site, the firm specializes in technology and healthcare.

A look at its holdings suggests a fondness for investing in energy and biopharmaceutical companies. Stakes include biofuel firm Verenium Corp., oil and gas firm Toreador, and energy firm TXCO Resources.

In the biopharma sector, holdings include shares of troubled cancer firm Tapestry Pharmaceuticals, biotech ImmunoGen, and infant respiratory company Discovery Laboratories.

See a list of the holdings here.