Some people use &quot;play the market&quot; to mean, &quot;I make investment decisions, and purchase stocks&quot;.  That&#x27;s the conventional meaning.<p>In this case, though, he&#x27;s contrasting the &quot;play&quot; as in &quot;fun&quot; aspect.  He doesn&#x27;t do it for fun, and instead treats it as work: minimizing risk, etc.<p>If I were &quot;playing&quot; this, I could do it with Fake Money and compare strategies over time, or invest pretend money to do all the same work.  I don&#x27;t think I&#x27;d be able to do it if gambling with real money.