Monthly Portfolio Review: September 2026

September added value to my ISA, but more importantly it changed the shape of my portfolio around the edges while my main concentration stayed intact.

This review covers my IBKR ISA only. It excludes my separate Trading 212 High Growth Challenge, and it is not a recommendation to copy my holdings.

My portfolio snapshot

Snapshot	IBKR ISA value
31 August 2026	£222,930.28
30 September 2026	£248,324.71
Change in displayed account value	+£25,394.43 (+11.39%)

This is not a claimed investment return. It is the change in my tracked account value between month-end snapshots, without a full cash-flow attribution. The useful number is the one that helps me keep the record honest, not the one that makes the month look most impressive.

What changed in my portfolio

My core positions remained 2,000 Rocket Lab shares and 250 Palantir shares. Around that core, my month-end records showed Surf Air Mobility at 20,000 shares, Strategy at 100 shares, Rome Resources at 6,000,000 shares and IonQ at 105 shares. Ondas appeared as a new 200-share position in my final snapshot.

Micron, IREN and GoPro did not appear in my 30 September snapshot after appearing at the end of August. That tells me my portfolio changed, but I will not retrospectively invent the rationale for every trade from a holding list alone.

Earlier in the month I wrote that I held some MSTR and BMNR for a little crypto exposure inside my ISA. I treated that as deliberate satellite exposure, not a replacement for the core investment case elsewhere in my portfolio.

What I was watching

• Whether my core concentration was still doing the job I wanted it to do, rather than just benefiting from a strong tape.
• Whether my satellite positions had a distinct reason to exist or were simply increasing the number of screens I watched.
• How much of the month’s progress was changing my behaviour, rather than my underlying conviction.

Where I could be wrong

I still carry meaningful concentration and execution risk. A stronger end-of-month value does not remove financing risk, dilution risk or the possibility that a company thesis takes longer to play out than I expect. My ISA is a proof asset for my process, not a blueprint for someone else’s allocation.

See my live Portfolio, the August 2026 review, and my relevant company writing through the RKLB archive.

Monthly Portfolio Review: August 2026

August was a reminder that a concentrated portfolio can make a month look straightforward in retrospect while feeling anything but straightforward in real time.

This is a retrospective record of the IBKR ISA only. It does not include the separate Trading 212 High Growth Challenge, and it is not a model portfolio or a recommendation to copy any holding.

Portfolio snapshot

Snapshot	IBKR ISA value
31 July 2026	£194,538.84
31 August 2026	£222,930.28
Change in displayed account value	+£28,391.44 (+14.59%)

That change is not presented as an investment return. It is the change in the tracked account value between the two month-end snapshots, without a full cash-flow attribution. The end-of-month record also matters more than a good-looking moment during the month.

On 25 August, I shared an IBKR screenshot on X showing £229,185.80 and a strong month-to-date move. The validated 31 August snapshot was lower at £222,930.28. That is a small but useful illustration of the point: a concentrated account can move enough in a few sessions to change the emotional story you tell yourself about the month.

What the portfolio looked like

The core stayed concentrated. The 31 August snapshot recorded 2,000 Rocket Lab shares, 250 Palantir shares, 2,001 AbCellera shares and 1,000 BETA Technologies shares. Smaller positions included 18,000 Surf Air Mobility shares, 80 Strategy shares, 1,000 QYLP units and several higher-risk satellite holdings.

I am deliberately not converting every native-currency position into a headline weighting here. The point of a monthly review is to record the shape of the decision, not manufacture more precision than the source data supports.

What I was watching

• Whether the concentration that created the upside would remain tolerable when the direction reversed.
• Whether I could distinguish a genuine thesis change from the discomfort of a volatile screen.
• Whether the portfolio was still serving the wider aim of freedom, rather than becoming a new source of compulsive monitoring.

Where I could be wrong

A small number of growth companies can create a result that looks rational while prices rise and fragile when sentiment changes. Execution risk, financing risk, dilution and valuation compression remain real. The lesson is not that concentration is automatically wrong. It is that concentration asks more of the investor than a good month can reveal.

See the live Portfolio, the previous July 2026 review, and the relevant company writing through the RKLB archive.

July was a month of making the portfolio more honest about where my conviction actually sits.

This review uses my IBKR ISA only. It is the account represented by the main Portfolio page. My Trading 212 holdings are part of a separate £15k High Growth Challenge and are not included in the figures or commentary below.

The figures are from my IBKR prior-business-day-close snapshot for 31 July 2026. They are a dated record, not live prices or a recommendation for anyone to copy my allocation.

Portfolio snapshot

At the 31 July close, the IBKR ISA was worth £194,538.84, including £49.84 of cash. The invested value was £194,489.00.

The separate Trading 212 challenge was worth £12,132.13 at its 31 July snapshot, including £136.74 cash. I am keeping it separate because the two accounts use different reporting timings and serve different purposes.

The main portfolio remains deliberately growth-oriented and concentrated. That is not a claim that concentration is safe. It is an acknowledgement that my returns, good or bad, will be shaped heavily by a relatively small number of positions.

Biggest changes in July

The biggest decision was increasing my Rocket Lab position from 1,000 to 2,000 shares. To fund that change, I sold Apple, Alphabet, NVIDIA and SoFi, and reduced Uber in the IBKR ISA. I wrote separately about why I made Rocket Lab roughly 50% of my portfolio, including the concentration, financing and execution risks I am accepting.

I also increased Micron from eight to 10 shares and Surf Air Mobility from 10,000 to 13,800 shares. These are material changes to a concentrated portfolio, so I want them recorded rather than quietly absorbed into an evergreen holdings page.

No quantity changes were identified in the Trading 212 challenge between its late-July reporting snapshots. Its three holdings at month-end were Uber, Amkor and AST SpaceMobile.

Current main holdings at month-end

At the 31 July IBKR close, the core positions included:

• Rocket Lab: 2,000 shares at $64.95.
• Palantir: 250 shares at $123.06.
• AbCellera: 3,001 shares at $5.71.
• BETA Technologies: 1,000 shares at $18.93.
• ServiceNow: 150 shares at $111.23.
• Surf Air Mobility: 13,800 shares at $0.76.

Those prices are the values in the dated broker snapshot. The live Portfolio page is the better place for the latest IBKR ISA holdings and indicative GBP values.

What I am watching

Rocket Lab remains the central position to watch, partly because of its size and partly because the investment case depends on execution continuing across several moving parts. The opportunity is why I own it. The concentration is why I need to keep looking for evidence that could challenge my view.

I am also watching whether the smaller positions continue to earn their place. Owning a company is not a permanent vote of confidence. I need to be able to explain what I am underwriting, what has changed and what would cause me to reassess.

For AbCellera in particular, the clinical proof points remain important. My latest AbCellera investment update sets out why the next programme milestones matter to the thesis.

Where I could be wrong

The obvious risk is concentration. A few disappointing outcomes at the same time would hurt this portfolio materially. That is especially true when growth companies can be volatile, funding needs can change and expectations move faster than the underlying businesses.

Another risk is confusing familiarity with understanding. Spending time researching a company can improve a thesis, but it can also make a view feel more comfortable than it deserves. The job is to keep testing the assumptions, not just to keep repeating them.

Finally, a positive month-end snapshot does not settle anything. I want the monthly record to show the decisions, the uncertainty and the areas where I could be wrong, rather than turn every portfolio move into a victory lap.

Final thoughts

July made the main portfolio simpler in one sense and riskier in another. I have fewer positions that matter, and more exposure to the ideas I believe in most. The trade-off is that I need to be more disciplined about reassessment when the screen is red as well as when it is green.

This is a personal portfolio record, not financial advice. The positions, prices and weights can change after the reporting date.