Atlas Venture this morning held its annual investor meeting in Boston, and led with some very large news: The firm plans to split in half, with its healthcare and IT groups to raise separate funds as independent entities.

The healthcare team will retain the Atlas brand, and plans to raise a new fund next year that would be similar in size to the $265 million Atlas raised for its ninth fund in early 2013. The IT team will come up with a new name – but keep the firm’s Cambridge, Mass. office space – and is expected to raise a fund that is around half as big, believing that its seed and early-stage strategy is best followed when each of its five partners have around $25 million or so to invest. [Update: I made an error here. The tech side has four partners, and the plan would be to raise around $160 million total.]

Atlas partners Bruce Booth (healthcare) and Jeff Fagnan (tech) say that the split is not being driven by performance, as each side of the house has similar returns over the past several funds. Instead, it’s just a belief that the two investment strategies have grown further and further apart over the year, and that being a generalist no longer makes sense. That said, the combined group will continue to manage existing funds.

This is just the latest evolution for Atlas, which at one point had a $750 million fund and multiple offices throughout North America and Europe. It refocused on the Boston market in 2009, while still making opportunistic plays in areas like Silicon Valley. The current teams are expected to remain the same, with the healthcare side recently adding former Epizyme president and CFO Jason Rhodes as a partner.

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