Strategist Still 'Pretty Bullish' On Stocks

Jason Trennert remains "pretty bullish" on the stock market. The chief investment strategist and managing partner at Strategas Research Partners told "Squawk on the Street" that his optimism is a simple matter of "supply and demand" -- and a lot of private equity.

Trennert explained to CNBC's Mark Haines and Erin Burnett that he calculates the amount of stock retired from the market and the amount of money in private equity -- where the "dominant investors" are found. The demand curve made for "pretty good" first-quarter earnings, and the strategist sees more to come.

Burnett asked what one can expect when private equity money and the "artificial" upward pressure of stock buybacks "go away." Trennert conceded that "this can end badly when it ends" -- but pointed to the "good news": "this will stay pretty good for a long time."