Billionaire trader Alex Gerko suffered a setback when the UK Supreme Court rejected his appeal over the tax treatment of his trading profits. The nine‑member bench held that the earnings, derived from a share of the firm’s net gains, constitute income rather than capital. The ruling overturns a lower‑court decision that had favored Gerko’s interpretation, raising concerns among other high‑frequency traders about future liabilities now.

The case stems from a long‑running dispute with HM Revenue & Customs, which argued the profits should be taxed at marginal rates up to 45 %. Gerko, who runs the quantitative fund GSA Capital, contended the returns were capital gains, a classification that would have halved his tax bill. The Supreme Court’s interpretation aligns the treatment of such profit‑sharing schemes with that of traditional employment income. The tax bill difference amounts to several million pounds, prompting Gerko to pursue the appeal through every judicial level.

Investors watch the decision closely because it clarifies the tax exposure of performance‑based compensation across hedge funds and proprietary trading firms. Firms may need to re‑model remuneration structures to avoid unexpected liabilities. The ruling also signals that the UK’s top court will not shy from treating profit‑sharing arrangements as ordinary income. Regulators may also review guidance to ensure consistent application across the industry.