Talk about following the money.
Investors looking to beat the need only track the companies that are spending the most money lobbying Washington.
Doing so would have generated profits that easily beat the index—generating alpha, as it's known among investing pros—every year for more than a decade, according to data from Strategas, which uses a proprietary measure it calls the Lobbying Index to track those companies.
"This Index has outperformed the S&P 500 for 15 consecutive years. Not only has the Index outperformed the S&P 500 in the first year, but holding that same Index leads to outperformance in the second and third years as well," the firm said in a research note Wednesday. "In our opinion, this consistent outperformance suggests that the market cannot properly value the return from company lobbying activities."
(Read more: Wall Street gears up to spend big on 2014 election)
From 2002-13, the index turned in an average annual return of 17.4 percent, compared to the S&P 500 gain of 6 percent, according to Strategas.
The index saw its relative performance weaken in 2010-2012 during an increase in correlations—or the tendency of stock prices to move in unison up or down—beating the S&P 500 by just 0.4 percent in 2010 and 4.4 percent and 3.6 percent in the ensuing years, respectively.
In 2007, the Lobbying Index topped the broader measure by 24.9 percent, and had an 8.7 percent edge in 2013. Over the past 26 months, the index has gained 82.4 percent, more than 28 percentage points better than the S&P 500.
(Read more: Big money is bullish on stocks, bearish on bonds)
Corporate America generally and Wall Street in particular, of course, spends huge money trying to get its way in Washington, particularly since Congress has amped-up regulation efforts following the financial crisis.
Total lobbying spending in 2013 hit $3.21 billion, off the all-time high of $3.55 billion in 2010 but still more than double the allocation from as recently as 2000, according to the Center for Responsive Politics.
Financial firms have been particularly active, leading all sectors with $484.6 million last year, followed by health-care firms—as Obamacare was being implemented—which spent $480.3 million.
Strategas, though, compiles its index with companies that spend the highest amount on lobbying as a share of total assets, and few are in the finance world and none of them are big Wall Street banks.
(Read more: There's just nomaking sense of this stock market)
The top five on the index in terms of lobbying are: 3M, Accenture, Alexion Pharmaceuticals, Altria and Brown-Forman.
The index includes 50 companies; the most-represented sector is industrials, with 10, while the least-represented is utilities, with just one.
—By CNBC's Jeff Cox. Follow him on Twitter @JeffCoxCNBCcom.
