The results, published on 27 May, land as SpaceX prepares a $1.75 trillion initial public offering that would further crystallise gains for SMT and its Edinburgh-based manager, Baillie Gifford. For any board overseeing a concentrated asset base, the trust's experience offers a live case study in portfolio construction, long-duration capital allocation, and the mechanics of private-to-public transitions.

What the numbers show

SMT's net asset value rose by more than 27 per cent in the twelve months to the end of March, according to the trust's final results filed with the London Stock Exchange. The SpaceX holding itself surged 179 per cent over the same period, leaving the rocket and satellite communications group as SMT's "largest holding by some margin," in the words of Christopher Samuel, the trust's chair.

The share price tells a parallel story. SMT stock rose 0.5 per cent on the day of results to 1,528p, taking the twelve-month gain to almost 55 per cent and the five-year return above 30 per cent, according to London Stock Exchange data. That five-year figure, however, still bears the scars of the broader growth-investing drawdown of 2022 to 2024. Samuel acknowledged that the travails of growth investing "continues to influence the company's five-year record," though he called the annual results "encouraging."

City AM analysis estimates that, based on the proposed $1.75 trillion IPO valuation, Baillie Gifford stands to return £3.5bn from SpaceX across its four flagship investment trusts. If realised, that would rank among the largest such returns in UK investment history. Baillie Gifford first backed SpaceX in 2018.

Matthew Hose, equity analyst at Jefferies, said the results "highlight limited portfolio activity, but continued very strong performance from the private investments," according to comments reported by City AM.

Concentration risk: governance lessons for operators

A single position comprising a fifth of a £16bn portfolio is, by any measure, unusual. Tom Slater, who has managed SMT since 2015, was direct about the implications.

"It would be remiss not to acknowledge the potential for volatility that comes with a position of this size."

Slater framed SpaceX not as an aerospace contractor but as "a dual monopoly: the world's dominant launch provider and a global connectivity utility with the potential for software-like margins," according to the trust's results statement. He attributed the valuation primarily to Starlink, SpaceX's satellite communications subsidiary, which he said "is building the kind of predictable, highly profitable revenue that the best software businesses aspire to."

Samuel, for his part, cast the concentration as a feature rather than a flaw, stating that it "highlights both the importance of access to leading private companies and the extent to which a small number of exceptional investments can drive long-term returns."

The governance question is worth isolating. SMT is a FTSE 100 constituent in its own right, with an independent board distinct from Baillie Gifford's fund management operation. That structure means the board must weigh fiduciary duty to shareholders against the manager's conviction-driven approach. For operators and finance directors at growth-stage businesses, the parallel is clear: when a single asset or revenue stream dominates, governance frameworks must account for both the upside optionality and the downside tail risk.

Samuel urged caution on time horizons, noting: "As in previous years, we emphasise that one year is too short a timeframe over which to assess performance. Our focus remains firmly on long-term outcomes."

From private to public: what the SpaceX IPO means for SMT's next moves

The proposed SpaceX IPO, at a $1.75 trillion valuation, would rank the company among the most valuable listed firms globally. Its 200,000-word prospectus references data centres in space, asteroid mining, and regular transports to the Moon and Mars, according to City AM's reporting.

For SMT, the listing introduces immediate mechanical considerations. A lock-up period in the run-up to the share sale will prevent private holders, including SMT, from selling. After the lock-up expires, the trust will face decisions about position sizing, capital recycling, and reinvestment.

Emma Bird at Winterflood, the City broker, said the IPO at the suggested valuation would "represent another seven per cent uplift on net asset value" for SMT, as reported by City AM. She added that Winterflood expects the managers "to be able to recycle these proceeds into attractive new long-term growth opportunities."

Slater appeared relaxed about the venue change. "A listing changes the venue in which a company's shares are traded. The opportunity and our reasons for owning it remain the same," he said in the results statement.

Hose at Jefferies described the IPO as representing "a key juncture for the position and the trust as a whole." The question of how, and how quickly, SMT trims or holds the position post-listing will be closely watched by analysts and shareholders alike.

Pipeline of listings and the AI thesis

SpaceX is not the only pre-IPO position on SMT's books. The trust holds stakes in Anthropic, Databricks, ByteDance (the owner of TikTok), and Stripe, the online payments platform. All four are considered potential listing candidates, meaning lock-up dynamics and private-to-public transitions will recur as a structural theme for the trust.

SMT views artificial intelligence as a generational opportunity. Samuel called it "the early stages of a profound technological transition," which the trust is meeting with a "long-term, globally unconstrained approach," including "maintaining exposure to selected Chinese companies where compelling opportunities exist," according to the results statement.

He elaborated: "Artificial intelligence is not simply another incremental innovation; it has the potential to reshape industries, alter competitive dynamics and change where value accrues across the economy. As with previous paradigm shifts, the ultimate winners are unlikely to be obvious in advance and may emerge from different geographies, sectors and stages of development."

The AI thesis ties directly to several of SMT's largest holdings. Anthropic and Databricks sit at the infrastructure and application layers of the AI stack; ByteDance deploys AI across recommendation algorithms at consumer scale. If these companies follow SpaceX to public markets, SMT's board will face repeated versions of the same concentration and recycling decisions it confronts today.

Historical pattern

SMT has navigated these inflection points before. Launched in 1909, the trust made early investments in rubber during the car ownership boom sparked by the Model T Ford, backed Chilean railways and Cuban telegraph companies, and was an early international investor in Japan when foreign investment rules were loosened in the 1980s. It doubled down on its long-term strategy after the dot-com crash in the early 2000s and subsequently backed Amazon, Tencent, and Tesla, earning its place on the FTSE 100 in 2017.

The SpaceX moment is, in that context, the latest iteration of a pattern: a concentrated, conviction-led bet on a category-defining company, held through private markets and into public ones. Whether the governance apparatus around that bet proves as durable as the returns remains the open question for SMT's board, its shareholders, and any operator watching closely.