Dr. Walden says, "Clearly low gas prices have helped. I think low gas prices is blunting any problems that's going to be caused in the economy by the slow housing market.

"Those prices being lower also coming at a good time right before the very important Christmas buying season -- ... I think that's helping the market.

"Inflation appears to be losing some of its threat, and of course gas prices are helping there -- and the stock market generally likes low inflation," he adds.

"Interest rates: another positive here. The Fed has stopped increasing interest rates. This makes stocks more valuable, so that's pushed the stock market up.

"And perhaps a lesser known factor: capital spending," he concludes. "Businesses are spending a lot of money on new equipment and technology. This is good for productivity. Again, the stock market likes good productivity."