Investing in the FTSE 100 has proven an exceptional way for investors to grab a second income down the years.

London’s premier share index is packed with financially robust companies with market leading positions in mature industries. When combined, these qualities can deliver large and reliable dividends over time.

Today the forward average dividend yield on Footsie shares sits at 3.5%. That’s not bad. In fact, it’s more than double the 1.1% for S&P 500 stocks, for instance.

Based on this, a £9,000 lump sum investment today could net me a total £630 in passive income in 2025 and 2026. But I think I can do much better by buying shares in Vistry Group (LSE:VTY) and Phoenix Group (LSE:PHNX).

Dividends are never, ever guaranteed. But if City forecasts are accurate, I’d enjoy a bumper £1,400 in dividends this year and next by spreading this lump sum across these two stocks.

Here’s why I’d buy them if I had spare cash to invest.

Stunning dividend growth

Vistry Group: total dividend income for 2025 and 2026 — £504

For next year, the dividend yield on Vistry Group shares is a FTSE 100-beating 4.8%. Combined with the potential for fresh share price gains, I think the builder could deliver an excellent overall return.

What really excites me is the potential for strong and sustained payout growth following the (predicted) return of dividends in 2024. City brokers think dividends will soar 42% in next year and by 32% in 2026.

This nudges the yield to 6.4%.

Trading performance is rapidly improving as the UK housing market rebounds, underpinning these bright forecasts. Vistry’s operating profit rose 10% in the first half as property completions advanced 9%.

There’s no guarantee that this recovery will continue, and especially if the domestic economy slows so risks remain. But with interest rates tipped to keep falling, I think the outlook for housebuilders like this is encouraging.

And with the new government pledging to pump up the supply of affordable housing, specialists in this area like Vistry are looking good for the long term.

10.1% dividend yield

Phoenix Group: total dividend income for 2025 and 2026 — £896

Financial services goliath Phoenix Group is also tipped to grow dividends over the short-to-medium term. Annual increases of 3% are tipped for each of the next two years.

As a consequencem the dividend yields for 2025 and 2026 are truly staggering. At 9.8% and 10.1% respectively, these are almost three times the Footsie’s current forward average.

Like Vistry, earnings at Phoenix are sensitive to changes in interest rates and its trajectory could easily be derailed. But thanks to a strong balance sheet, I don’t expect Bank of England policy decisions to impact dividends in the short term at least. The firm’s Solvency II capital ratio was an excellent 176% as of June.

This was near the top end of its 140% to 180% target.

I’m backing the FTSE 100 firm to continue delivering market-beating rewards beyond 2026 as well. This will be driven by a likely surge in pensions demand as the UK population rapidly ages.