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Investors who focus on FTSE 100 and FTSE 250 stocks may be missing out on excellent opportunities elsewhere. There are roughly 2,000 companies on the London stock market to choose from, giving plenty of scope to find the next breakout UK growth shares.
Most investors know about Rolls-Royce‘s stunning share price ascent — it’s up 87% in 2025 alone. But some lesser-known UK stocks have performed even better since 1 January.
Here are two that have delivered greater price gains, and which I think could continue outperforming the FTSE engineer.
Caledonia Mining
Gold producers have been among the best-performing stocks this year as bullion prices have surged. The yellow metal’s appreciated 57% in 2025, hitting new peaks above $4,100 an ounce in recent days.
Against this backdrop, Caledonia Mining‘s (LSE:CMCL) share price has rocketed 229% since 1 January. Its outperformance reflects the fact that miners’ profits can grow faster than gold prices — their fixed costs mean any extra revenues flow straight into the bottom line.
During quarter two, Caledonia’s EBITDA (earnings before interest, tax, depreciation, and amortisation) increased 52% year on year (excluding gains from asset sales). This surged past the 9% rise in gold prices over the period.
I’m confident yellow metal prices can keep rising, driven by global trade tensions, rising inflation, weak growth, and the falling US dollar. I think Caledonia may be one of the best ways to capitalise on this fertile environment given its excellent operational record.
The company delivered record second-quarter production from its Blanket Mine in Zimbabwe. It now expects to produce 75,500 and 79,500 ounces of gold in 2025, up from a previous forecast of 73,500 to 77,500 ounces.
Caledonia only has one working mine and a number of exploration assets. As a consequence, it’s more vulnerable to production outages than gold stocks with multiple active projects. But on balance it’s still an excellent share to consider, in my view.
Frontier Developments
It’s been tough for video game developers in recent years as consumers have tightened their belts. Uncertainty remains for these tech shares given the murky economic outlook.
But Frontier Developments (LSE:FDEV) has managed to defy the gloom and deliver impressive share price gains in the process. The company — best known for the Elite Dangerous space flight simulator — is up 122% in the year to date.
Frontier’s revenues are recovering strongly as it doubles-down on its core business of creative management simulation (CMS) games. Sales across these titles rose 25% in the 12 months to May, helping the developer to return to profit.
A raft of new CMS titles could deliver a sustained rebound for the gaming giant. Jurassic World Evolution 3 is set for release this October. Two further titles are slated for release in the next few years.
With a strong balance sheet, Frontier has room to invest for future growth while also returning cash to shareholders. It launched a £10m share buyback programme over the summer.
