Share buybacks are the market's hidden backbone - Goldman Sachs says these 13 stocks will get the biggest boost from them through 2019

• Share buybacks have kept the equity bull market afloat for years, and there's great value to be gleaned from knowing which companies are going to see the biggest impact from them.
• Goldman Sachs has identified the 13 stocks set to get the largest boost from share repurchases through the end of 2019.

For much of the nine-year equity bull market, share buybacks have provided stock-price appreciation during stretches devoid of other positive catalysts. As such, they've served as a safety net of sorts for stocks, forming a solid backbone of continued strength.

And if activity so far in 2018 is any indication, they're going to continue to be a major force.

The amount of share repurchases executed by S&P 500 companies is expected to hit $650 billion this year, which would shatter the record set in 2007 and mark a 25% year-over-year increase, according to Goldman Sachs data. The same goes for announced buybacks, which are expected to swell to $900 billion, also an all-time high.

With that in mind, it's clear there's a major investing benefit to identifying the companies poised to buy back the most shares. But Goldman takes it a step further.

The firm piggybacks off the idea that buying back shares reduces a company's share count, which automatically pushes its stock higher. After all, the firm's total market value is the same before and after the repurchase, so any recalibration must be done through the stock price.

What Goldman then does is single out the companies expected to see the biggest decline in shares outstanding through the conclusion of 2019. Based on the mechanics outlined above, these stocks can be fairly described as those likely to gain the most from buybacks.

Without further ado, here are the 13 stocks in the S&P 500 expected to see the biggest decline in share outstanding from now until the end of next year.