There isn’t much everyone agrees on in markets. But one thing you rarely hear an argument against is the importance of trading as little as possible. The higher your turnover, the higher your costs go and the worse your overall performance will be. So find good quality stocks you have faith in and hold them for the very long term—Warren Buffett or Nick Train style.

Or maybe don’t. On this week’s episode of Merryn Talks Money, Michael Spencer, the billionaire behind one of the world’s biggest financial brokerage fortune, says the low turnover story is old hat. There has been a change in market structure, he says, and trading costs today are “microscopic” compared with even a few years ago.

So if the valuation of a share changes in the short term, why not trade it? After all, if you want to differentiate yourself in a market biased towards passive strategies, being genuinely active can’t be a bad thing. With that in mind, Spencer has become a big backer of asset management firm Nutshell and its manager Mark Ellis. Ellis has a “very, very good track record” as a derivatives trader, says Spencer, and uses those skills to “process the data of literally tens of thousands of stocks worldwide, from Japan to the US.” Listen in for more details.