While stronger technology spending across Wall Street and a spell of innovation at Cisco have boosted the stock to post-recession highs, shares now look a little expensive, according to Normura Instinet.

The brokerage downgraded Cisco's stock to neutral from buy on Friday, arguing that the strong stream of IT purchases that has buoyed shares may reverse in 2019 to "reveal imperfections in Cisco's story."

"Through 2018, IT spending growth accelerated materially, Cisco's new Catalyst 9000 series more than tripled its customer count, and Cisco's software mix hit about 25 percent of sales. These drivers helped Cisco exceed consensus estimates through 2018," analyst Jeffrey Kvaal wrote in a note to clients.

"However, spending may be wobbling; comments from Dell, HPE, and Broadcom suggest incremental caution in chief investment officer thinking," Kvaal added. "Cisco's ongoing product refresh leaves it insulated, though not immune, from a slowdown."

The analyst reiterated his 12-month price target of $50, which implies just 5.3 percent upside over the next year from Thursday's close of $47.47. That price target yields a multiple of about 15 times Nomura's calendar year 2019 earnings per share expectation of $3.33.

Shares of Cisco fell more than 2 percent in premarket trading following the downgrade; shares are up 23.9 percent this year.