NEW YORK — Sure, the Internet shakeout has slowed, but the mighty still can take a tumble in cyberspace — and it’s just happened at Forrester Research. The prominent, Cambridge, Mass.-based Internet consultant revealed it plans to lay off 126 people, or about 22 percent of its workforce worldwide.

Forrester estimated it will take a one-time charge of roughly $5 million related to the workforce reduction during the first quarter ending in March. Cost savings associated with the layoffs are expected to range between $18 million and $20 million annually. In addition, Forrester reiterated its forecast for the fourth quarter ended Dec. 31, 2001, projecting it will weigh in with earnings of about 21 cents a share on sales of around $34 million. The company expects to report its fourth-quarter and full-year results on Jan. 30.