It's about to get a lot easier to bet on the backbone of the stock market

The world's biggest provider of exchange-traded funds is giving US investors a new way to bet on companies that repurchase their own shares.

iShares, the ETF provider within investment titan BlackRock, just filed a registration statement with the US Securities and Exchange Commission for a fund that will track stocks with a history of share buybacks and dividend payments.

The iShares US Dividend and Buyback ETF (ticker to-be-determined) is designed to track the Morningstar US Dividend and Buyback Index, which itself provides exposure to the companies with the largest dollar value spent on the two activities.

While there's already a healthy handful of dividend-focused ETFs available for trading in the US, it's the buyback component to the new iShares fund that's intriguing. For the entirety of the eight-year bull market, repurchases have served as a handy backstop for companies, serving as a reliable driver of stock returns.

Ultimately, they're a win-win for corporations who want to push their stock higher by reducing shares outstanding while also signaling to the market that they see shares as undervalued. And, perhaps most importantly, it's a tactic that can generate returns during lean times, like the S&P 500's five-quarter earnings slump, a period that saw the index still grind out a 1.5% gain.

It's easy to see why investors would want exposure to companies that are repurchasing shares. Since the start of the bull market, the S&P 500 Buyback Index - which consists of the 100 companies with the highest ratio of cash spent on buybacks versus total market cap - has surged 417%, far outpacing the benchmark S&P's 266% gain.

This is not to say that iShares is the first provider to offer a buyback-focused ETF. There's also the $1.3 billion PowerShares Buyback Achievers Portfolio, which tracks an index of US companies that have repurchased at least 5% of their shares outstanding over the past 12 months.

Not to mention the $139 million AdvisorShares Wilshire Buyback ETF, which uses research from Wilshare Associates to invest in companies that aren't increasing leverage and have positive cash flow.

And last but not least, there's the SPDR S&P 500 Buyback ETF, which is essentially a non-starter with a market cap of just $8.6 million.

Even with these buyback-focused ETFs already in existence, it's still significant that BlackRock iShares, the biggest fund provider, is taking an interest in the investment strategy. At this point, the initial filing has been made, and it remains to be seen how popular the fund will be. But one thing's for sure: it's in good hands.