Silicon Alley Insider reports that Twitter is looking to raise a Series C round.

They’re hearing that the company wants $15M at a $60M valuation, probably from former investors Union Square Ventures and Charles River Ventures, and perhaps from Spark Capital as well.

Twitter raised over $5M in funding last July. Digital Garage also invested in the company this past January as part of Twitter’s expansion into Japan (the only market where Twitter is actually making money).

The news of this Series C comes on the heels of a couple significant departures.