What happened

Shares of Intuitive Surgical (NASDAQ:ISRG) rose 10.2% in August 2018, according to data from S&P Global Market Intelligence. The maker of the da Vinci robotic surgery platform and its associated tools didn't need any actual news to keep its impressive market momentum going.

So what

August started out with analyst firm Citi boosting its price target on Intuitive Surgical from $561 to $592 per share, triggering a modest jump in the company's stock prices that day. I am not privy to the reasoning behind Citi's bullish action, but other analysts published optimistic reports in late July based on accelerating procedure growth and an increasingly clear view of growth in the robotic surgery sector for many years to come.

Near the end of August, Intuitive Surgical got a second wind for no obvious reason. Smaller rival TransEnterix (NYSEMKT:ASXC) posted an even larger gain in the second half of last month, again for no better reason than a bounce back from the preceding couple of weeks of negative market action.

A robotic hand pushing keys on a laptop, where the screen shows a complicated chart of some sort.

Image source: Getty Images.

Now what

August may not have given investors any fresh insight into Intuitive Surgical's business prospects, but robotic surgery clearly looks like a solid idea in general. Today, we Intuitive Surgical investors can look back at a market-crushing 48% return over the last 52 weeks while TransEnterix left us far behind with a 174% gain. Fellow Fool Keith Speights expects this sector to extend those gains for years to come, and I can only nod in agreement.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.