What a Year of Writing Publicly Taught Me About Investing
2025 marks my first full year on Substack. Over the past year, I’ve published more than 100 articles, every single week. I’m more proud of some than others.
I’ve experimented with formats, discovered a wide range of businesses, improved my writing (at least I hope), and learned a ton along the way.
If you’re reading this and you’re thinking about writing down your investing journey, even if it’s just for yourself, don’t hesitate. Start. You might not be a good writer today, but you’ll get better. And even if the writing doesn’t matter to you, do it for the investing. Writing forces you to think, and that alone makes you a better investor.
Reflecting On The Newsletter’s Value Proposition So Far
The end of the year is a fantastic moment to pause, look back, reflect, and most importantly, look ahead.
Back in April, I launched my paid tier with the following promise: premium members would receive one investment thesis per month, monthly portfolio updates, stock and valuation updates after major events like earnings calls, and access to my stock research platform, Summit’s Analytics.
I want to take a moment to reflect on the value I’ve delivered so far, and how I plan to improve it going forward.
First, the good. Premium members did receive one investment thesis per month. In some months, I even published two. Each was a high-conviction idea, researched in depth.
But not everything has worked well.
My investment thesis posts often lacked clear guidance, a firm and actionable stance, and proper follow-up. Too often, I wrote about a stock I found interesting and then moved on, instead of tracking it, revisiting it, and updating my thinking as new information comes in.
Part of this comes down to a conflict of incentives. To justify a subscription, I feel pressure to constantly deliver new stock ideas. That has pushed me to spend more time hunting for the next idea, instead of spending time on what I already know well: the stocks I own or closely follow.
But more ideas aren’t necessarily better. And focusing too much on discovery comes at the expense of depth and consistency. All the while, I haven’t stopped to think about what it is you want, why you subscribed in the first place.
In other words, I’ve come to realize that my value proposition is flawed, and implicit. I’ve never clearly articulated what I’m actually trying to offer you as a subscriber.
The same issue applies to my monthly portfolio updates. While they’ve been useful in some ways, they also create the wrong incentives. I find myself focusing too much on short-term performance. After a bad month, I feel anxious. Does this look bad publicly? Will subscribers question my ability as an investor?
This goes directly against all my principles.
I’m a long-term investor. I focus on buying good businesses at attractive prices. That usually means buying when sentiment is poor, not when performance looks good.
Over the past month, I’ve spent a lot of time thinking about the value I offer today, and the value I want to offer tomorrow. That’s also part of the reason why I’ve been a bit less active recently.
To reset, I went back to the basics. What is is that you, as a subscriber, actually want? Why are people on Substack reading about stocks and investing in the first place?
You’re not here for raw information. Earnings numbers, financials, and news are everywhere. You’re here for interpretation and context. For learning how to think about investing. You’re trying to learn how to fish, not just be handed a fish.
Stock ideas are already abundant on Substack. Me adding more to an already crowded pool doesn’t necessarily add lots of value.
That doesn’t mean I’ll stop writing about new stocks. But I will shift my focus toward what’s already there: the companies I own and the ones on my watchlist.
Investment thesis posts will remain central. I’ll explain why a business is interesting, how it works, and what needs to happen for the stock to justify its current price. These posts will be highly similar to my thesis posts today, with one important difference: I won’t forget about them.
Alongside each investment thesis, I’ll provide a one-page “thesis ledger”—still not sure about the name—for premium members. This ledger will summarize the thesis, my buy stance, and my price targets.
Each ledger will be updated after relevant events such as earnings calls or major news. I’m also planning to integrate these thesis ledgers into Summit’s Analytics very soon, where both you and I will be able to create, save, and review our own one-page theses’ in a single click.
I’ll continue to cover earnings calls for the companies I own and follow, and I’ll explicitly update my theses as new information comes in.
There will be some kind of library or catalogue for premium members to view all the theses’ I’ve written about.
Premium members will, of course, continue to have access to Summit’s Analytics. A rebrand is coming soon, as the platform will be positioned more clearly as a distinct part of the value proposition. The newsletter and the platform serve different purposes, and that should be reflected more clearly.
One thing will not change: I remain deeply focused on improving the platform and turning it into a reliable, everyday partner for stock research. It’s not where I want it to be yet, but patience is key.
Portfolio updates will also remain part of the newsletter. Reviewing my portfolio regularly has been extremely valuable for me, especially on the psychological side of investing. What will change is the focus on short-term performance. I will no longer review portfolio performance on a monthly basis. I’m still deciding on the right interval, but quarterly, semi-annual, or even annual updates make far more sense.
Lastly, free content will remain integral to my newsletter. Since launching the premium tier in April, I’ve been experimenting with free versus paid content and how to find the right balance. This is an ongoing process. Alongside investment theses, stock updates, and portfolio updates, my final “content pillar” has been educational investing content. I’ve been taking a step back from this type of content, but want to focus more on this again. I write these posts partly to learn myself, and I think it’s naive to think I’m done learning.
All this translates into the following value proposition for you:
As a subscriber, you get a structured way to become a better long-term investor: clear investment theses that are revisited over time, transparent portfolio decisions, educational context on how to think about stocks, and a research platform to do the work yourself.
I also want to involve you more closely in my process.
Going forward, I plan to share my post schedule ahead of time, so you’ll know what to expect and when. In addition, I want to make better use of the subscriber chat, for both free and paid subscribers. I’m still thinking about the best ways to use the chat, but the goal is to make the process more open and interactive.
For January 2026, here’s my preliminary post schedule. I emphasize preliminary because things inevitably change. An important event might occur that I want to write about first, I may need more time to refine a post, or I might realize halfway through that a topic isn’t as valuable as I initially thought. Think of each schedule as a preview of what’s to come, not a fixed agenda.
January 2: Vail Resorts Q1 2026 review and thesis update
January 6: Improving the DCF and reverse DCF model in Summit’s Analytics, based on Michael Mauboussin’s work
January 9: Greggs Q4 2025 review and thesis update
January 14: Uber investment thesis
January 21: Distinguishing good companies from exceptional ones
January 29: ASML Q4 2025 review and thesis updateI’ve intentionally left some space toward the end of the month to allow for flexibility as January unfolds. Besides, February is shaping up to be a very busy month, full of Q4 earnings.
2025 Portfolio Update
Now, that is all for my 2025 newsletter review and my plans for 2026 so far. I now want to briefly focus on the actual portfolio, what I’ve learned in a full year of investing while writing on Substack, and the mistakes I’ve made.
I will not hide the truth by saying performance has been great so far. The portfolio has underperformed the S&P 500 index in euros. The currency impact is important, as I’m based in Europe, and a large portion of my portfolio is invested in stocks listed in U.S. dollars. This has been a significant headwind so far.
Nevertheless, since inception in July 2024, the portfolio has returned 7%, compared to 15% for the S&P 500 in euros.
Again, not great, but there are some caveats.
First of all, the S&P 500 consists of an established group of large-caps, with a mix of well-performing and poorly performing companies. Since I’ve only recently established and built out the portfolio, I’m largely invested in stocks that are currently in a dip and face negative sentiment (e.g., Novo Nordisk, Salesforce).
I am willing to accept long periods of flat performance or underperformance in exchange for buying at better valuations.
That said, I have made mistakes that I’ve hopefully learned from. And more importantly, by sharing them, I hope you can learn from them as well.
Investing is a game of reading the expectations embedded in a stock price and deciding for yourself whether those expectations are too high—meaning you should sell—or too low—meaning you should buy. Buying strong businesses alone is not enough. If the business is strong but expectations are unrealistically high, you’ll still underperform.
This is the essence of investing, and it’s something most people miss, because they are taught buying good businesses alone is enough. The price you pay does matter, and understanding expectations, as well as how and when they might shift, is critical.
This is where I’ve had shortcomings. Too often, I bought stocks too early and too aggressively, without enough conviction. I didn’t understand the context of sentiment and near-term catalysts as well as I should have.
For instance, I bought Novo Nordisk during the first half of the year when sentiment was turning negative and the price reached around 400 DKK. There is a type of FOMO in buying stocks that isn’t talked about enough. I’ve learned that I have an urge to buy too soon and too much whenever a stock is in a dip, believing I’ll miss the opportunity if I don’t buy.
But missing an opportunity is much better than losing money. Remember Buffett’s first rule of investing. I’ve learned that I need to be more patient not just with holding stocks, but especially with buying stocks. Buy slowly into a position, see how the situation develops, and buy more as conviction grows (or sell quickly when it fades).
I’ve also lacked structure when assessing stocks, especially when comparing them against each other. Too often, I value stocks in isolation and make a decision without considering the stocks I already own.
It often goes like this: “Oh, great, this stock looks fantastic to own and it’s at a good valuation. Let’s buy.”
Whereas the process should be: “Oh, great, this stock looks fantastic to own and it’s at a good valuation. But how does the quality of the business and its expected returns compare to what I already own? Does this stock deserve a spot in the portfolio?”
This is what matters. A stock needs to earn your conviction. And since we can choose from thousands of stocks, I need to be stricter in my stock picking selection going forward.
These are valuable lessons I’m taking with me into 2026, and I hope you’ll stick along for next year and the many years that follow.
Next month’s portfolio update will go into greater depth on my portfolio positions, transactions, and other details, just like my usual updates. The only change is that I won’t be reporting performance every month. As usual, next month’s portfolio update, and those that follow, will be exclusive to premium members.
Thanks for reading, and I wish you a Happy New Year.
Lucas
Author & Founder, Summit Stocks
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Disclaimer: the information provided is for informational purposes only and should not be considered as financial advice. I am not a financial advisor, and nothing on this platform should be construed as personalized financial advice. All investment decisions should be made based on your own research.
Thanks for this. Also closing out my first year. Fun to hear your reflections. Very similar to mine. Have a great 2026 and let’s keep in touch.
Looking forward to 2026, Summit!