Which firm led Pinterest's $27 million funding round in October 2011?

Andreessen Horowitz led Pinterest’s $27 million funding round in October 2011. The investment valued Pinterest at approximately $200 million and helped finance the young company during its rapid rise in users and attention.

Pinterest’s growth had accelerated after its March 2011 iPhone-app launch, which generated more downloads than expected. The company was still operating on a small scale, with its founders and programmers working from an apartment until mid-2011, but the service was beginning to attract major investor interest.

The round was not Pinterest’s first outside financing. Earlier in 2011, the company had secured a $10 million Series A led by Bessemer Venture Partners. FirstMark Capital and Bessemer also participated in the later $27 million round, but Andreessen Horowitz was the lead investor. That distinction makes the other listed firms incorrect answers.