Uncertainty around interest rates, fiscal policy, trade, and next month's midterm elections mean it's a good time for investors to be defensive, Elevation Partners co-founder Roger McNamee told CNBC on Thursday.

"The economy is still strong, but there are an awful lot of signals out there that suggest that equity prices are going to suffer relative to more conservative things," such as Treasuries, McNamee said on CNBC's "Squawk Alley."

In Thursday's volatile session, stocks were under pressure, one day after the Dow Jones Industrial Average and plunged more than 3 percent each, and the Nasdaq lost nearly 4.5 percent.

McNamee, an early investor in Facebook, said that despite the wild swings in trading, the fundamentals of the market have not changed much over the last year.

"We've lived in an environment where the expectation was that interest rates would be up, you've got higher inflation on the horizon, you've got major changes going on in the U.S. fiscal policy, in terms of tax cuts, you've got major changes in our trading policy," McNamee said. "I think all of that backdrop is finally catching up to the market."

Michael Nathanson, founding partner at MoffettNathanson, emphasized that some major technology companies are falling especially hard because they all have their own idiosyncratic issues.

Interviewed with McNamee on CNBC, Nathanson said Snap could be running out of money; Twitter's costs are ramping up into 2019; Facebook had weak second-quarter guidance; and Netflix, with its reliance on subscribers, is "just harder to defend if rates are rising."

Snap and Facebook are down 54 percent and 13 percent year-to-date, respectively. However, Twitter is up 12.6 percent. Netflix is up about 70 percent year-to-date.

Especially going into the midterm elections next month, McNamee said he feels more comfortable with stock shorts, or bets that equities will fall.

"The election is the next major milestone," he added. "I don't want to own anything long, because rates are going up, so I own things very, very short."

But McNamee also qualified that his approach is a very personal one.

"I'm at an age where I don't want to have to try to earn it all back," he continued. "We all have different risk profiles and we should invest accordingly. And for me right now, this is a time to be defensive."