The PowerShares Buyback Achievers Portfolio (NYSEArca: PKW) is up more than 35% this year and closed Monday with $2.27 billion in assets under management, $1.83 billion of which flowed into the fund this year,

That makes PKW the third-best PowerShares ETF when it comes to 2013 inflows and that is saying something because the firm issues 115 ETFs. http://www.invescopowershares.com/flows/

This is not the first time PKW, which celebrates its seventh birthday this Friday, or its underlying index, have topped marquee U.S. benchmark indices.

“The NASDAQ US Buyback Achievers Index is having a very good year. It the last 12 months, the Index is up +43.35% which easily outperforms the NASDAQ US Benchmark Index, up just +31.62% over the same period. In fact, the Index has outperformed the US Benchmark Index over the last 2, 3, 5, and 10 year periods as well. The index has outperformed the US Benchmark’s size segments as well, though by varying amounts,” according to NASDAQ OMX Global Indexes.

As the table below indicates, the NASDAQ US Buyback Achievers Index has a penchant for outperforming its benchmark as well as large- and small-cap indices.

Chart Courtesy: NASDAQ OMX Global Indexes.

Here’s a look at the NASDAQ US Buyback Achiever Index on a total return basis against its NASDAQ US Benchmark. The former crushes the latter over the past three years.

Chart Courtesy: NASDAQ OMX Global Indexes

And here is a look at how PKW has performed against its top three holdings, which combine for just over 14% of the fund’s weight, and Apple (NasdaqGM: AAPL). Apple is in the midst of one of the largest buyback plans in U.S. history and Carl Icahn is pushing for more. The stock is not yet a member of the NASDAQ US Buyback Achievers Index, but Apple is on the path toward meeting the index’s standards for entry. The point is stock-picking among companies that announced buybacks, broadly speaking, has worked this year. But PKW has this year and has in the past outpaced many of its holdings, confirming that stock-picking among share repurchasers is a strategy that could easily lag PKW and the NASDAQ US Buyback Achievers Index.