Passive income investing mistakes cost real money, and three in particular trip up even experienced dividend hunters. BT Group (LSE: BT.A) and Greencoat UK Wind (LSE: UKW) offer a study in each one.
Three Passive Income Investing Mistakes Worth Knowing
The first is dividend greed: chasing the highest available yield without verifying that the underlying cash generation can sustain the payout.
Vodafone is the textbook case. The group cut its dividend by half in 2025, and its final dividend for the year ending 31 March 2026 stands at 2.25 eurocents per share, per Vodafone investor relations. Many investors now regard the rebased payout as an attractive starting point.
At the time of the cut, portfolios built around the old yield took an immediate hit to their income stream.
The reverse error is treating a high yield as automatically suspect. Greencoat UK Wind carries a yield of around 10% and has raised its dividend ahead of inflation for 12 consecutive years. Its 2024 final results show a declared dividend of 10 pence per share for the year ended 31 December 2024, with a 2025 target of 10.35 pence per share.
The company’s Greencoat UK Wind investment case page puts the 2026 target at 10.70 pence per share, increasing in line with CPI inflation. That follows a policy shift from RPI tracking confirmed in January 2026, per a flash update from Kepler Trust Intelligence, a marketing communication commissioned by the company. The same update placed net asset value at 133.5p on 30 January 2026, reduced by 2.6p after changes to the Renewables Obligation scheme.
The Greencoat UK Wind 2024 annual report records 49 operating wind farm investments with net generating capacity of 2GW. Net cash generation for 2024 was £278.7 million. Asset values remain under pressure, a genuine risk, but the 12-year dividend growth record is an audited fact.
BT Group and the Total Return Blind Spot
The second mistake is measuring success only by income received while ignoring what happens to the share price.
BT Group carries a forecast yield of around 4.1% for the current year. At its FY26 results in May 2026, the company reiterated its commitment ‘to grow the dividend by low to mid single digit percent per annum in FY27 and onwards.’ The full-year dividend for the year to 31 March 2026 was 8.32 pence per share, per BT Group FY26 results on Investegate.
The share price has fallen 53% over the past ten years. For the year to 31 March 2026, BT reported revenue of £19.7 billion, down 3%, adjusted EBITDA flat at £8.2 billion, and reported profit before tax up 8% to £1.4 billion, per those same results.
The cash flow picture is improving. Normalised free cash flow reached £1.5 billion in FY26, and BT’s FY26 results PDF projects this rising to approximately £2.0 billion in FY27 and approximately £3.0 billion by the end of the decade. The same document records gross annualised cost savings of £580 million achieved in FY26, with the overall transformation plan target raised to £3.7 billion and the programme extended to FY30.
None of that invalidates BT as an investment. But a decade of share price decline sits alongside every dividend payment received, and total return is the only complete measure.
Sector Concentration: The Silent Portfolio Risk
The third of these passive income investing mistakes flows naturally from the first two. Apply rigorous income screens, find the companies that pass, and then notice the portfolio is concentrated in energy infrastructure, utilities, and telecoms.
It happens for a structural reason: those sectors reliably produce the highest yields on UK equity income screens. Investors also tend to overweight businesses they understand well. The outcome is a passive income portfolio carrying concentrated sector risk that was never a deliberate choice.
The regulatory change that trimmed Greencoat UK Wind’s NAV by 2.6p in a single update, and the decade of structural pressure that cut BT’s share price by more than half, both show what concentrated sector exposure can do to long-term outcomes.
These passive income investing mistakes share a common root: selecting on yield alone and screening out context. With BT’s free cash flow guided toward approximately £3.0 billion by end of decade, and Greencoat’s dividend now anchored to CPI, the fundamentals behind each yield number deserve at least as much attention as the yield figure itself.
