Impax Asset Management (LSE:IPX) and Polar Capital (LSE:POLR) are both AIM-quoted specialist fund managers. Each built its reputation on a focused Investment theme rather than a broad product range. In 2026, those themes have produced opposite results.

Polar Capital, best known for its technology and Artificial Intelligence (AI) funds, reported Assets of £45.0 billion at 30 June 2026, up 47% in three months. Impax, which specialises in investing in the transition to a more sustainable economy, reported £23.3 billion at the same date after another quarter of net outflows and a sharp fall in half-year profits.

That contrast is why the pair is instructive. Specialisation can deliver rapid growth when a theme is in demand, and prolonged outflows when it is not. This is an analytical comparison based on each company's latest reported figures.

Specialist managers and the power of a theme

A specialist manager's Revenue depends on assets under management (AUM), which move with two forces: net flows, meaning client money in minus money out, and market performance. A manager concentrated in one theme is heavily exposed to how that theme performs and how investors feel about it.

Sustainable and environmental strategies attracted large inflows earlier in the decade but have since faced redemptions across the industry. Technology funds, by contrast, have benefited from investor Demand linked to AI. Both companies describe themselves as AIM-quoted, so they sit outside the FTSE 100, FTSE 250 and FTSE SmallCap indices; we have not verified their FTSE AIM index membership.

Impax: outflows, lower profits and cost cuts

Impax's interim results, published on 20 May 2026, covered the six months to 31 March 2026. AUM fell to £22.3 billion from £26.1 billion at 30 September 2025, with net outflows of £3.6 billion, mostly from listed shares. That was still an improvement on net outflows of £10.2 billion in the same half a year earlier.

Revenue declined 23% to £58.8 million. Adjusted operating profit fell to £11.3 million from £20.5 million, and the adjusted Operating Margin narrowed to 19.2% from 26.8%. Adjusted Diluted Earnings per Share were 7.4p against 12.6p, and the Interim Dividend was halved to 2.0p.

Management responded with cost reductions, saying it expected to remove about 30 roles, around 11% of headcount, in the second half of the financial year. It is also broadening its range: it launched its first US exchange-traded fund (ETF) in February, and fixed income and systematic share strategies each represented roughly a tenth of AUM. In private markets, its fourth private-markets fund, of €459 million, completed its investment phase in 2025 with 13 investments across seven countries.

The Q3 AUM update of 10 July 2026 showed AUM of £23.3 billion at 30 June 2026, helped by £2.7 billion of positive market movement. Net outflows were about £1.75 billion, of which £754 million, around 43%, related to the anticipated exit tender at Impax Environmental Markets plc, an investment trust it manages. Chief executive Ian Simm pointed to most strategies outperforming relevant indices and improving trends with the group's largest distribution partner.

Polar Capital: technology-led growth

Polar Capital's results for the year to 31 March 2026 showed AUM of £30.6 billion, up from £21.4 billion, with net inflows of £902 million. Average AUM rose 14% to £26.0 billion.

Net management fees increased 10% to £196.9 million, although the average fee margin dipped to 76 basis points from 78 (one basis point is one-hundredth of a percentage point). Performance fees nearly doubled to £31.7 million. Core operating profit rose 11% to £62.8 million, with a core operating margin of 32%, unchanged. Adjusted diluted earnings per share rose to 57.8p from 52.6p, while the total dividend was held at 46.0p.

Strategically, management described its approach as "scale through differentiation and focus". It is reviewing its product range, including selected fund closures, and aims to concentrate on around 12 to 15 investment teams where it sees clear performance, capacity and client demand. Healthcare and convertibles strategies also contributed positively during the year.

Growth then accelerated. Polar's AUM update of 9 July 2026 reported £45.0 billion at 30 June 2026, with £2.5 billion of net inflows and £11.9 billion from market movement and fund performance in a single quarter. Chief executive Iain Evans said client demand was led by the Technology and AI funds.

Polar is also returning capital through buybacks. A 17 July 2026 announcement extended its programme, which began on 16 January 2026, to the Annual General Meeting on 24 September 2026. By then it had repurchased 1,847,908 shares at an average of 712.60p, with about £1.9 million of the programme remaining.

Comparing the two stories

The figures show that market performance has helped both companies, but flows diverge. Impax's AUM rose in the June quarter only because markets offset outflows. Polar's assets grew from both sources at once.

On our reading, Polar's margin advantage reflects scale and performance fees, while Impax's margin has been squeezed by falling revenue against a cost base built for a larger business. The periods differ, however: Impax's figures are half-year and Polar's are full-year.

Risks and dates to monitor

Concentration cuts both ways. Much of Polar's recent growth came from market gains in technology holdings, so a sharp correction in technology shares could reverse a large part of it. Performance fees are also volatile from year to year.

For Impax, the key questions are whether outflows ease once the Impax Environmental Markets tender is complete, whether cost savings restore margins, and whether new products such as the US ETF gain traction. Impax's financial year ends on 30 September 2026, so, based on its announcement history, its next quarterly AUM update and full-year results are the main checkpoints. Polar's quarterly AUM updates will show whether the momentum of the June quarter continues.

What the contrast shows

Impax (LSE:IPX) and Polar Capital (LSE:POLR) offer contrasting specialist asset-management stories because their chosen themes are moving in opposite directions with investors. Polar is currently benefiting from demand for technology and AI, while Impax is cutting costs and diversifying as sustainability-focused outflows continue. Neither position is permanent, and both remain highly sensitive to the performance of the markets they specialise in.