(UPDATED with minor editing changes.)

Venrock Associates, the venerable Rockefeller-founded VC firm in Menlo Park, Calif., plans to expand its investments in publicly traded biotechs, VentureWire reports (subscription required).

The venture firm, which allocates roughly one-third of its funds to healthcare-related investing, said it will set aside about 10 percent of its latest $600 million fund for public-company investments in biotech. Venrock backed four public biotechs in its last fund, and now plans to invest in as many as three public biotechs every year over the next three years.

From VentureWire:

[General partner Anders] Hove, who is leading the effort, said there are many public biotech companies with promising products but relatively little cash….

The firm typically looks to fund clinical-stage companies with market capitalizations in the $300 million- to $350 million-range. The partners generally don’t want to take board seats on public companies, he said. Since the company’s fortunes – and the firm’s investment – are tied to the success of clinical trials, there’s not much a board member can do to help the company, he said.

Venrock has been bringing in new blood to work on public deals, and also plans to have William Rastetter, the former executive chairman of Biogen Idec who joined the VC firm last year, evaluate such investments.