California-based companies received about 56 percent of all U.S. venture capital dollars in 2014, the state's highest share of venture activity since the dot com boom of the early 2000s. Over the past 15 years, investment activity has steadily become more concentrated in California and a few other states. In 2009, about 67 percent of all deals and 74 percent of venture capital dollars flowed to the top five states. By 2014, those states' share of venture dollars grew to 80 percent, according to NVCA/Pricewaterhouse Coopers data.

In the first three quarters of 2015, U.S. venture capital firms have invested $47.2 billion, more than the year-end totals for 17 of the past 20 years, according to new data from the National Venture Capital Association (NVCA) and PricewaterhouseCoopers (PwC). About $16.3 billion was invested in 1,070 deals in the third quarter, bringing the 2015 total to $47.2 billion in 2,239 deals. Investment activity is on track to reach its highest annual level since 2000, and the second highest year since the beginning of PwC’s Moneytree report.

Biotech is in the midst of an investment boom, at least in Silicon Valley. In the first quarter of this year, biotech firms in the region raised $574 million, the third highest quarter on record, according to data from PricewaterhouseCoopers (PwC) and the National Venture Capital Association (NVCA) and reporting by the San Jose Mercury News. This peak represents a 103 percent increase over the same quarter the previous year.