I finished reading The Davis Dynasty: Fifty Years of Successful Investing on Wall Street this week. The book chronicles three generations of the Davis family and how an initial $50,000 investment in stocks by the patriarch has turned into more than $2 billion for the family and an investment firm that manages over $25 billion in total assets.

This book caught my eye because I enjoy learning about “investor entrepreneurs” —investors by profession who don’t want to work for someone else, so they choose to become entrepreneurs by starting companies that invest capital

In the 1940s, the Davis family patriarch had a unique insight about insurance companies. He realized that (1) the companies had hidden investment portfolios that would compound for long periods until claims were paid out, but they were disguised as unprofitable companies because of accounting rules, and (2) the market for life insurance was exploding because of World War II. He quit his job in 1947 and became a full-time investor specializing in the stocks of insurance companies. His timing proved ideal: his portfolio ballooned from $50,000 to roughly $10 million by 1959.

One key takeaway from this book is the patriarch’s insistence on writing and distributing a weekly bulletin about the insurance industry. In the early 1990s, his grandson began helping him write this newsletter. He asked why they should bother when the lack of feedback suggested that no one was reading it. The patriarch’s response? “It’s not for the readers. It’s for us. We write it for ourselves. Putting ideas on paper forces you to think things through.”

The patriarch used the weekly bulletin as a tool for reflection and learning. Distributing it to others added accountability to the process.

When I read this, I thought about a few successful founder friends with a similar habit—which I remembered because it’s rare. They’ve built companies worth hundreds of millions of dollars or more. Each sends a weekly email update to their investors and/or team. They’ve kept up with this habit for years, since their earliest days. I asked one of them why he keeps doing it. He does it for himself, he said, not the recipients. It forces him to reflect on the past seven days and plan for the next seven.

I’m a proponent of founders sending update emails. It’s a habit with superpower potential. Everyone can do it, and because few people do, it gives those who take the time for it an edge.