NEW YORK (TheStreet) -- U.S. companies aren't the only ones spending billions of dollars on share buybacks. Many foreign companies are doing it as well.  

Investors can take advantage of this trend through ETFs that track companies with significant share buybacks, which are intended to boost the stock's price by reducing the number of shares in circulation.

In the U.S., there's  the popular PowerShares Buyback Achievers Portfolio (PKW) - Get Report. For an international play, there's the lesser-known PowerShares International Buyback Achievers Portfolio  (IPKW) - Get Report.

The PowerShares International BuyBack Achievers Portfolio is up 15.3% this year, a performance that is nearly 50% better than the MSCI EAFE Index, one of the most widely followed developed market benchmarks. The international fund is also more than triple the returns posted by the U.S. version of the ETF.

The PowerShares International Buyback Achievers Portfolio tracks the Nasdaq International BuyBack Achievers Index, which requires companies to "have effected a net reduction in shares outstanding of 5% or more in its latest fiscal year."

Additions and deletions are made to the index once a year in July. The U.S.' PowerShares Buyback Achievers Portfolio follows the same methodology, but its index makes changes in January. Companies are eligible for inclusion in the two buyback ETFs after they have reduced shares outstanding by 5% over the trailing 12 months.

Said another way, the mere announcement of a repurchase program, even a large one, does not guarantee a company admission into either of the PowerShares buyback ETFs. The 5% reduction in shares outstanding threshold must be met. That requirement is significant because it must be met every year for a company to remain in the buyback indexes, ensuring IPKW and PKW hold shares of companies that are consistent repurchasers of their own stock.

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PKW has a new competitor, the SPDR S&P 500 Buyback ETF (SPYB) - Get Report. That ETF focuses on "the 100 companies in the S&P 500 with the highest buyback ratio in the last 12 months. The buyback ratio is defined as the ratio of the total cash put toward buybacks in the trailing year and the market capitalization of the company as of a reference date," according to State Street.

IPKW is smaller and younger than its domestically focused relative, but that has not stopped the $41 million international buyback ETF from delivering impressive 2015 gains. With interest rates low throughout the developed world, foreign companies are taking a page from the playbook of their U.S. counterparts, boosting buybacks with cheap debt. That could bode well for IPKW. 

Japanese stocks account for more than 30% of IPKW's geographic weight, nearly double the weight the ETF assigns to Canadian stocks. The fund's weight to Japan is important because after years of cash hoarding, Japanese companies are increasingly boosting buybacks.

For the 12 months ended in March, Japanese dividends and buybacks surged 76% to $104 billion.  With Japanese companies holding more cash than firms in any other major developed market, the trend of increased buybacks there could be in the early innings. Nine of the 10 consumer discretionary stocks held by IPKW are Japanese companies.

Canada, IPKW's second-largest country weight, is no slouch on the buyback front, either. A dedicated buyback index of Canadian firms with the highest buyback ratios has easily outperformed the benchmark S&P/TSX composite index over the past decade.

In just the past two weeks, at least five Canadian companies have announced buyback programs, including Air Canada and BlackBerry.

Europe also figures into the international buyback equation, which is good for IPKW because the fund allocates almost 18% of its weight to European countries, excluding the U.K. Outside of the U.K., European firms repurchased just $125 billion of their own shares last year, but pressure is intensifying on European companies to take advantage of low interest rates and part with some of their more than $2 trillion in cash by increasing buybacks.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.