And the winner is ... swing-state stocks It's all about swing states in today's presidential election. So here's another swing-state nugget, courtesy of Jack Ablin, chief investment officer at BMO Private Bank. Swing-state stocks have outpaced the Standard & Poor's 500 index during President Obama's first term. That's based on the collective performance of companies that are either based in a swing state or that do a lot of business there. The S&P 500 has notched an average annual gain of 12.1% during the Obama administration. Every one of the nine battleground states that Ablin analyzed has fared better, ranging from 15.7% for Ohio to a whopping 59.1% for Nevada. Nevada benefitted from big gains in gold-mining companies and a surge in Las Vegas Sands Corp. The next-best showings were Florida and Iowa, each up 29%. The stock performance isn't unexpected given that the economies of battleground states generally have fared better lately than the national economy as a whole. Stock performance won't have a significant effect on the election, but every little bit helps in a tight presidential election. "If stock market returns influence elections, Obama will be helped," Ablin wrote in a report to clients. Prosperity in swing states may be key in presidential race Follow Walter Hamilton on Twitter @LATwalter