It is time to take some profits on the red-hot video gaming stocks after a huge run, according to one Wall Street analyst who nailed the rally.

Cowen reduced its rating for Activision Blizzard shares to market perform from outperform, citing the risk its new esports league will do worse than expected.

This is the firm's first downgrade of the video game maker in nine years, according to its analyst. Activision Blizzard shares have risen more than 600 percent since the end of 2008 through Friday versus the S&P 500's 182 percent return.

"We remain confident about the trajectory of Activision's core business, with Call of Duty likely to rebound this year and Black Ops 4 likely due for release next year. However, we have a significant bit of nervousness around the debut of Overwatch League," analyst Doug Creutz wrote in a note to clients Monday.

The analyst said a significant portion of Activision Blizzard's valuation premium versus its industry peers is "based on investor optimism around the potential for esports to be a large profit generator in the future."

The company's vaunted Overwatch esports league is slated to launch on Dec. 6 with 12 teams.



"As this is the first time a publisher has ever attempted to launch a major esport from scratch, we expect OWL 1.0 to be a learning experience, and thus believe that the probability of reality failing to meet investor expectations is relatively high," he wrote.

Activision Blizzard and Take-Two shares are up 75 percent and 118 percent respectively year to date through Friday compared with the S&P 500's 14 percent return.

The analyst reiterated his $66 price target for Activision Blizzard shares, representing 4 percent upside to Friday's close.

Creutz also lowered his rating to market perform from outperform for Take-Two shares Monday, citing concerns over the company's lengthening gap between title releases.

While Take-Two's "digital initiatives have certainly borne fruit, the frequency of highly successful title releases still has a significant bearing on the company's average earnings power," he wrote.

"From a tactical perspective, we also believe that many investors are in TTWO shares specifically in anticipation of RDR 2's release, with a meaningful risk of a post-launch sell-off in shares."

Red Dead Redemption 2 is scheduled to be released in the spring of 2018, nearly eight years after the first Red Dead Redemption. The analyst reaffirmed his $83 price target for Take-Two shares, representing 23 percent downside to Friday's close.

Shares of Activision Blizzard and Take-Two declined 2.8 percent and 3.5 percent respectively midday Monday following the reports.

Activision Blizzard and Take-Two did not immediately respond to requests for comment.