Passive income investors who waded into the market and bought Fortescue Ltd (ASX: FMG) shares five years ago will have banked some outsized returns by now.

On 8 May 2020, shares in the S&P/ASX 200 Index (ASX: XJO) mining stock closed the day trading for $12.04. That came after Fortescue shares had already rebounded by 25% from the COVID-driven lows in early March that year.

So, we're not cherry picking any particular lows here.

Despite the massive uncertainty and global border closures during that pandemic-addled time, Fortescue still paid out two fully franked dividends in 2020. And it's done so every year since.

So, how much passive income would an $8,000 investment in Fortescue shares have returned by now?

Let's find out!

Drilling into Fortescue shares for passive income

At $12.04 a share, you could have bought 664 Fortescue shares five years ago, with enough change left over for some chips.

You'd then have been eligible to receive the second (final) Fortescue dividend of 2020, along with the miner's next nine passive income payouts. Fortescue's most recent interim dividend of 50 cents per share was paid on 27 March.

The highest payout over the five years was the final dividend of $2.11 per share, paid on 30 September 2021. That record dividend was spurred by soaring profits as the iron ore price hit US$220 per tonne in July that year.

All told, the 10 fully franked dividends you've received since 8 May 2020 amount to $10.87 per share.

Meaning the 664 Fortescue shares you bought five years ago for $8,000 have already returned $7,217.68 in passive income. With potential tax benefits from those franking credits.

Let's not forget those capital gains

Atop that welcome passive income, the Fortescue share price has also see-sawed higher over the past five years.

Despite iron ore prices slipping back below US$100 per tonne at the end of April, the Fortescue share price closed on Wednesday at $16.09.

So, if you wanted to, you could have sold those 664 shares for $10,683.76.

Now, let's add back that $7,217.68 in passive income you'd have banked from those 10 dividend payouts.

That brings the accumulated value of the Fortescue shares you bought five years ago for $8,000 to $17,901.44 today.

Or a gain of 123.8%.

We'll find out how much Fortescue will pay for its final FY 2025 dividend when the ASX 200 miner reports its full-year results in August.

Stay tuned!