Hansen Medical, Inc. (HNSN: chart) priced its initial public offering of 6.3 million shares at $12 per share, in the midpoint of the forecast range of $11 to $13, raising $75 million. All of the shares were offered by Hansen and represent a 30% stake in the company.

The lead managers of the offering were Morgan Stanley and J.P. Morgan, while Thomas Weisel Partners and Leerink Swann acted as co-managers.

Hansen Medical has granted the underwriters a 30-day option to buy up to 937,500 additional shares to cover over-allotments.

Hansen Medical, based in Mountain View, California, was founded in 2002 to develop products and technology using robotics for the accurate positioning, manipulation and stable control of catheters and catheter-based technologies.

The company stock closed at $12.79 on Friday, up 6.6% from the IPO price.

Natural-gas partnership Constellation Energy Partners LLC (CEP: chart) offered 4 million limited liability units on Wednesday, priced $21, the high end of the $19 to $21 expected price range, raising $94.5 million.

Shares closed the first day of trading at $21.95 a share, up 5% from the IPO.

The offering represents nearly 40% stake in the company.

Citigroup and Lehman Brothers were the lead underwriters for the offering.

The company has granted the underwriters a 30-day option to buy up to 675,000 additional common units to cover over-allotments.

The Baltimore-based company was formed by Constellation Energy Group (CEG: chart) in February 2005 to acquire coalbed methane reserves and production.

The company’s shares ended the week at $23.01 per share, up 9.6% from the IPO price.

The oil and gas exploration company Venoco Inc. (VQ: chart) on Thursday offered 12.5 million shares that was priced at $17 per share, below the estimated range of $19 to $21, raising $212.5 million.

The offering represents about a 29% stake in the company.

Credit Suisse, Lehman Brothers, and J.P. Morgan were the underwriters on the deal.

The underwriters have an option to purcahse 1.88 million additional shares to cover excess demand.

The company’s shares closed at $17 per share on Friday, unchanged from the initial offering price.

DECLINERS:

Biopharmaceutical company Emergent BioSolutions Inc. (EBS: chart) on Wednesday priced its initial public offering of 5 million shares at $12.50 per share, below the expected range of $14 to $16 a share. All of these shares were sold by the company.

J.P. Morgan acted as a lead manager for the offering with Cowen & Co as joint lead manager and HSBC Securities as co-manager.