Generating a reliable passive income from a portfolio of FTSE 100 shares is one strategy investors use to fund retirement.
A Stocks and Shares ISA offers an appealing structure for this approach, as all growth and dividends remain free of tax for life.
A monthly income target of £1,750 works out at £21,000 a year, and the amount of capital required depends heavily on the yield achieved.
At a 4% yield, an investor would need approximately £525,000 in their ISA to reach that annual income figure.
A 5% yield reduces the required sum to around £420,000, while a 6% yield brings the target down further to approximately £350,000.
Plenty of FTSE 100 shares currently offer generous income, with insurer and asset manager Aviva (LSE: AV.) standing out as one of the highest-yielding blue-chip stocks at a trailing yield of 6.3%.
The Aviva share price has climbed 55% over five years, though momentum has slowed considerably, with the stock up just 2.6% over the past 12 months.
Geopolitical tensions, including concerns that rising oil prices could push inflation higher and keep interest rates elevated, have left Aviva looking choppy despite several years of steady pre-tax profit growth.
Pre-tax profits have risen from £1.350bn in 2022 to £2.203bn in 2025, representing a strong upward trajectory across the period.
The trailing price-to-earnings ratio currently stands at 23.3, well above the FTSE 100 average of around 16, though on a forward basis using 2026 earnings, it drops sharply to 12.1.
Analysts forecast the dividend yield to reach 6.66% in 2026 and 7.11% in 2027, though dividends are never guaranteed and investors should treat such forecasts with appropriate caution.
Aviva recently spent £3.7bn acquiring Direct Line, and the integration of systems, operations and staff presents execution risk that could erode anticipated cost savings if management missteps.
Insurers also remain exposed to the claims cycle, meaning expensive weather events or rising motor repair costs could quickly squeeze profitability despite broader Business momentum.
The company has identified the business pension risk transfer market as a growth opportunity, though competition in that space remains fierce and is unlikely to ease in the near term.
On balance, the income prospects appear strong and the valuation does not look excessive on forward earnings, making Aviva a stock worth monitoring closely for any dip this summer.