Aviva (LSE: AV.) shares are attracting growing attention from passive income investors — and it’s not hard to see why.

Forecasts suggest the FTSE 100 insurer’s dividend could rise 5% to 41.3p per share next year, giving the stock a chunky forward yield of around 6.6%.

That’s comfortably ahead of the wider FTSE 100 average and could allow investors to target a surprisingly large second income.

So how many Aviva shares would an investor need? And how realistic is that goal?

Crunching the numbers

To generate £1,000 a month in passive income, an investor would need to target £12,000 a year in dividends.

Based on Aviva’s forecast 41.3p dividend per share, that would require 29,056 shares.

At today’s share price of £6.20, building a position of that size would cost approximately £180,147.

That’s clearly a substantial amount of money. However, this should be viewed as a long-term end goal rather than something investors need to achieve upfront.

In practice, many investors aim to build towards it gradually through regular monthly investing, while reinvesting dividends along the way to purchase additional shares. Over time, that combination can significantly accelerate progress towards the income target.

So, does Aviva make a good long-term investment?

Sustainable dividend

For income investors, the key question isn’t what the dividend looks like today — it’s whether the underlying earnings power can realistically support continued growth over time.

One of the main reasons I remain bullish is the way the group is reshaping its earnings mix.

Beyond its traditional insurance operations, the wealth and retirement division is becoming increasingly important. Management is targeting around £280m of profit from wealth by 2027. Already, the division makes up nearly 10% of group earnings. That means it’s no longer a side business — it’s becoming a meaningful second engine of income.

In my view, that shift matters because it gradually tilts more profits towards steadier, fee-based cash flows rather than purely cyclical insurance earnings.

What to watch

That said, I don’t think the insurance cycle risk should be ignored. UK motor and home insurance markets have clearly softened in recent periods, which can put pressure on underwriting margins.

The acquisition of Direct Line also placed additional strain on the balance sheet. Solvency II ratio — a key measure of an insurer’s financial resilience — fell as a result. Although, at around 180%, it remains comfortably within a healthy range.

The key question for investors is whether the expected cost and capital synergies from the deal are fully realised over time. If they are delayed or fall short, that could limit flexibility around capital returns in the years ahead.

Offsetting this, in my view, is management’s proven ability to navigate the cycle. Through disciplined pricing, scale advantages, and a dominant UK market position across multiple lines of business, Aviva has consistently shown it can protect profitability even in tougher conditions.

Looking further ahead, an increased use of AI across pricing, claims handling, and customer service has the potential to structurally improve the cost base.

So where does that leave investors today? In my view, Aviva shares still look like a compelling income opportunity. It’s not a risk-free dividend story, of course — investing never is. But the combination of scale, cash generation, and improving efficiency makes it a stock I think income seekers should mull over.