Owners of guns have been stocking up because they are concerned about a potential tightening of regulations on assault weapons in the president's second term.
In October the number of background checks on people applying to buy guns, an indicator of future sales, increased by 18.4 per cent.
There was a similar jump when President Obama was first elected in 2008. A total of 12.7 million background checks were carried out that year, up from 11.2 million the year before, and the number has been rising since then.
Shares in weapons manufacturers like Smith & Wesson and Sturm, Ruger also surged after Mr Obama's re-election.
The gun control debate in America was re-ignited by the July 20 massacre at a cinema in Aurora, Colorado, in which suspect James Holmes is accused of killing 12 people and injuring 58 during a screening of Batman film The Dark Knight Rises. He used a semi-automatic rifle with a 100-round magazine.