If you're investing for passive income and bought ANZ Group Holdings Ltd (ASX: ANZ) shares five years ago, you'll have earned some outsized returns by now.

And not just from the S&P/ASX 200 Index (ASX: XJO) bank stock's reliable, twice-yearly dividend payments. You'll have enjoyed some strong capital gains as well.

Now, if you turn the clock back five years, to market close on 20 March 2020, you may recall that very few people were buying shares at that time. Not for passive income. And not for capital gains.

This was during the early months of the global COVID-19 pandemic, after all. And most ASX 200 stocks had been in freefall for the past month.

But if you were among the brave few to wade in and buy the dip in ANZ shares when there was blood in the streets, here's what a $10,000 investment would be worth today.

Five years of passive income from ANZ shares

Five years ago, you could have picked ANZ shares for $15.89 apiece.

That means for $10,000, you could have bought 629 shares in the ASX 200 bank stock with a bit of pocket change left over.

At market close on Thursday those same shares were trading for $29.16 each. Meaning your 629 shares would now be worth $18,341.64.

That's $8,341.64 in capital gains.

So, how about that passive income?

Well, if you bought and held onto those shares since March 2020, you would have received 10 ANZ dividend payments by now. And with the exception of the past three dividends, which were franked at 70%, 65%, and 56%, respectively, those dividends have come fully franked.

That means you should be able to hold onto more of that passive income at tax time.

All told, those 10 dividend payouts work out to $6.89 a share.

My trusty calculator then tells me the 629 ANZ shares you bought for $10,000 five years ago will already have returned $4,333.81 in passive income.

Adding that back into yesterday's closing price of $29.16, the accumulated value of ANZ stock bought on 20 March 2020 has soared to $36.05 a share.

Those shares then will have delivered a combined passive income and capital gain of $20.16 each.

And the 629 shares you acquired for $10,000 would have returned a total of $22,675.45. Or a gain of 127%.

As for investors buying the ASX 200 bank stock today, at Thursday's closing price, ANZ shares trade on a partly franked trailing dividend yield of 5.7%.