How UK shares could build a £339,849 ISA

A UK-focused Stocks and Shares ISA, funded with £250 a month, could grow to about £339,849 over 30 years at an 8% annual return. The analysis compares modest monthly contributions with long horizons, noting that tax-free income and capital gains apply within an ISA. Scenarios range from 6% to 10% annual returns, yielding £237,175 at 6% and £493,482 at 10%, illustrating how compounding matters. The piece notes that 42 FTSE 100 members have outperformed Microsoft over five years, underscoring the appeal of domestic equities. SSE is highlighted as an example, delivering near-8% annual returns since June 2021 and reflecting the sector's growth potential. The author stresses that outcomes depend on market returns and individual circumstances, including monthly cash flow. Even optimistic assumptions acknowledge that top performers' gains include outliers such as Rolls-Royce. An 8% annual return is framed as a realistic long-term target for UK shares when kept disciplined. The piece underscores SSE's role in the clean-energy transition, supporting the case for domestic exposure. Readers are advised to perform due diligence and seek professional advice before committing capital.