Shares of the Stamford, Conn. were rising 17.1% to $231.08 on Tuesday.
Gartner reported income of $164.1 million, or $1.84 a share, compared with $75 million, or 83 cents a share, a year ago. Adjusted earnings came to $2 a share, beating analysts' consensus estimates of $1.05 a share.
Revenue totaled 1.1 billion, up 8.4% from a year ago, and slightly above Wall Street's expectations.
Looking ahead, Gartner said it expects to report 2021 adjusted earnings of about $6.25 a share, compared with forecasts of $4.19.
Gartner said it expects to report net income of roughly $471 million.
"We had an outstanding start to the year with strong growth in contract value, revenue, EBITDA and free cash flow," CEO Gene Hall said in a statement. "Given robust demand and effective cost management, we have meaningfully updated our 2021 guidance."
Hall said the company repurchased more than $600 million of stock through the end of April "reflecting our commitment to return significant amounts of free cash flow to shareholders."
During the quarter, Gartner repurchased 2.3 million common shares for $398 million. Operating cash flow came to $157 million.
In March, Bank of America added Gartner to its US 1 list, noting the company was "well positioned for a cyclical recovery and revenue acceleration beginning by mid-year."
"Adding in its newfound commitment to expanding margins, its cash generative business model, and a likelihood of meaningful buybacks, Gartner appears poised to deliver mid-teens+ annual EPS growth in 2022 and beyond," BofA said.