With the solid post-IPO performances of Splunk and Tableau Software, Big Data continues to be on the mind of investors, and momentum is accelerating.

Big Data is getting even bigger in 2013. From Hadoop distributors to text mining platforms, private Big Data companies raised $1.28B across 127 deals in the first half of 2013. With an average of over $210M in funding and more than 20 financing deals per month, industry pundits will have some credibility when they inevitably describe 2013 as the “year of Big Data”. From 2008 to 2012, we’d seen $4.9 billion invested in Big Data companies but given 2013′s activity-to-date, it’s obvious that interest and activity levels are ramping up.

Big Data exit activity in 2013 is also heating up, as highlighted below. The first six months of the year saw a total of 22 M&A transactions and 3 IPOs including the strongest VC-backed Tech public offering in Q2 2013, Tableau Software. Last year’s high-flying Big Data IPO, Splunk, has seen its market cap jump nearly $2B since its first day of trading, and this should portend good things for Big Data companies as investor sentiment is high.

In the past year, 10 investors have completed six or more deals for Big Data companies including Lightspeed Venture Partners, which has backed the likes of MapR Technologies and BloomReach among others. Accel Partners which launched its second $100M Big Data Fund in June is also atop the most active leaderboard. The top 10 most active investors in Big Data over the last year is below.

A list of the 30 most well-funded private Big Data companies can be found on the ‘Research’ tab, after logging in to CB Insights. (Note: This research is only available to paid subscribers with access to CB Insider.)