Welcome
The world of finance needs talented people. And talented people, in order to flourish, want to learn. In the past 15 years, social media have provided an avenue for curious, ambitious people who sought information about markets and investing. Their landscape changes all the time. 20 years ago there was a Reddit precursor, named Phynance. It is long dead, but fondly remembered. Then we had Stack Overflow-like sites for finance; Stack Overflow is not doing so well these days. Then Twitter/X had its moment in the spotlight. Reddit also exists, mostly as an embittered, content-free version of the old Phynance. LinkedIn is a place for stultified posts and status signaling. Of all new initiatives of recent years, Substack seems the most successful, balancing curated content, a well-designed platform, and a sustainable financial model. Of course, it is already well established for independent public intellectuals. Most recently, it has hosted some excellent technical and finance blogs, like arg min by Ben Recht and MoonTower by Kris Abdelmessih. On a personal level, I crave better ways to communicate and help people. I started posting on X nearly two years ago. I was on a non-compete, had relative freedom, and was sharing drafts of a book I was writing, and that was published this year (2025). I also posted less often on LinkedIn. This social media experiment has been surprisingly successful. Including my small poetry X account, I have almost 100,000 followers. My goal, however, is not to accumulate followers. It is to communicate meaningfully with people, and even more broadly, to pack my days with as many meaningful acts as I can. One of the best experiences you can have in life is to meet a stranger, strike a conversation, and leave after one hour saying “This was really good. I feel I got something out of talking to you. Thanks.” I would like this to happen especially for bright students and early-career finance professionals who are trying to figure things out, both personally and technically. When this happens, it’s a great feeling. The planets of the Solar System, and the humans living in it, are a little closer, and that’s a very good thing. It does not happen often on X any more, and definitely doesn’t happen on LinkedIn. Hence, Substack. It has many desirable features for me.
Zero followers-to-few-followers. This is a feature, not a bug. It’s great to start from zero, and attract only people willing to spend more than 10 seconds on something. Substack is not designed for outrage, but for thought. I like that. It also allows me to have more one-on-one interactions.
Long-form content. In a decent-quality typographic setting. No screenshots of formulas. No tweetstorms. This is really the main benefit of Substack.
More freedom of expression. Having more committed readers means that I find something interesting that is not strictly financial (book passages, literature, pictures, random thoughts) I can post them.
A few notes on content and frequency of posting. My professional life is hardly a secret. However, this newsletter has nothing to do with work. My finance posts will be strictly educational, and technical in content. You may get the impression that I read book or do math all day long at work. But my long days are filled by meetings and very practical tasks. I read, write, and do arithmetics at night and during the weekends. This overload of theory should be no problem for my readers. “Great minds discuss ideas; average minds discuss events; small minds discuss people.” (E. Roosevelt). As a corollary, I won’t even mention competing firms, allocators, people in finance, etc., other than in some historical context. And of course, none of this will be even remotely interpreted as “investment advice”. If you think it does, please let me know privately and I will consider editing the content. Also, don’t expect high-frequency posting but weekly content, or less. Consider me the anti-Matt (Levine, whom I love). Here is what you should expect:
Half-formed ideas
Cute/useful results (I will re-post some useful stuff from my X feed)
“Public readings” of papers/books I have come across, and trying to understand (we don’t do enough of this). I will do only for “good” papers
“Words of un/wisdom”, e.g., “you and your quant research”
Material that I would like to include in 2nd editions of my books
Memes (I will probably cross-post those to other platforms, why not)
Some pointers to literature (mostly nonfiction and poetry) I like
I will still use LinkedIn for memes and event announcements, and X for announcements and links to Substack.
My posts on Substack will remain free for the foreseeable future.
P.S.: the title of the blog comes from the Latin palindrome “In girum imus nocte et consumimur igni”, which describes well both the activities of moths, the lives of finance professionals, and the human condition.



Godspeed Gappy. If there were more people like you the world would be a nicer place
Looking forward to learning!