Hot Topics in Tech: The worst start to the year since forever. Unfavorable light shining on China, raising the debate on circuit breakers. NASDAQ uses blockchains in the first large-scale trade, or so they say. Symbiont disagrees. Will blockchains be the HFT of 2016? The tech opportunities created by the regulatory environment. What have SEFs done to the world of swaps?

The Inbox: Listener questions and comments

• Comment from Jim B. - Will there be TTT awards for the best and worst developments of 2015?
• Question from George S. - How far are we away from being able to be a professional prop trader from a beach in Tahiti? When can we do all of this from our smartphones?
• Question from Big Bob - Is there open source software in the finance industry?
• Question from Sarah R. - Can you explain what a matching engine is and how it works?
• Question from Leo10 - Who was your favorite guest from 2015?
• Question from Jim B. - What is the optimal tech set up for the aspiring active retail trader?