ANN ARBOR – Arboretum Ventures LLC is raising a new fund of $215 million, according to a form filed with the U.S. Securities and Exchange Commission, what would be the largest VC fund in Michigan, Crain’s Detroit reported Thursday.

The previous largest was the $180 million raised in 2013 by Farmington Hills-based Beringea LLC for its Michigan Growth Capital Partners II fund.

Because of SEC regulations restricting publicity for VC firms that are raising money, Tim Petersen, a co-founder and managing director of Arboretum, declined to comment about how much may have been raised so far or when the firm hopes to finish fundraising. His co-founder is Jan Garfinkle.

Arboretum finished raising its last fund, of $138 million, in 2011. The company had planned to raise a $125 million fund then, but it was oversubscribed because of a recent string of successful exits for its portfolio companies.

In 2008, Ann Arbor-based HealthMedia Inc., a wellness website, was sold to Johnson & Johnson for about $200 million.

In 2010, Ann Arbor-based HandyLab Inc., a medical device company, was sold to New Jersey-based Becton, Dickinson and Co. for $275 million.

In 2011, Ann Arbor-based Accuri Cytometers Inc., another medical device company, was also sold to Becton, Dickinson for $205 million.

In 2013, Arboretum had another successful exit when Ann Arbor-based Esperion Therapeutics Inc. executed an initial public offering of $73 million.

In March of this year, Esperion raised $190 million in a secondary offering.

Arboretum was founded in 2002 and finished raising its first fund of $24 million in 2005. It closed on its second fund of $73 million in 2009.

According to its website, the company has invested in more than 30 companies. The six companies for which Arboretum has had exits have an aggregate valuation of about $3.5 billion.