Yahoo! co-founder Jerry Yang has stepped down from the search giant's board and "all other positions" at the company, effective immediately.
"The time has come for me to pursue other interests outside of Yahoo!" Yang said in a letter announcing his resignation to board chairman, Roy Bostock.
Yang's resignation comes a fortnight after the appointment of PayPal president Scott Thompson as CEO, though Yang claimed in the letter that he was "enthusiastic" about Thompson's appointment.
"I am grateful for the warm welcome and support Jerry provided me during my early days here," Thompson said in a statement.
Yang has held various roles at the company since founding it with Stanford classmate David Filo in 1995, including a short stint as CEO between 2007 and 2009.
His resignation also affects roles he currently holds on the boards of Yahoo Japan and Alibaba Group.
Yahoo! announced Yang's decision after close of trade on NASDAQ on Tuesday evening but shares climbed as much as 6.8 percent in after-hours trading.