David Spillane, the most senior Irish executive at Facebook, has sold more than half of his shares in the social media giant as the lock-in period for insiders ended.
Mr Spillane serves as the €35bn firm's chief accounting officer at its HQ in California. Other Irish executives at Facebook include Colm Long and Sonia Flynn at its European base in Dublin.
Chief operating officer Sheryl Sandberg offloaded €5.84m worth of shares, with general counsel Theodore Ullyot also selling in recent days.
Mr Spillane sold 256,000 shares, netting around €4.25m. He had more than 863,000, including unvested shares, according to an SEC filing last May -- potentially worth €26m when the company floated last summer.
Facebook floated in May, with shares priced at $38 (€30) each. But fears over the company's future growth trajectory and uncertainty over how it could make money from mobile devices, saw a massive sell-off.
Shares in the social media giant have fallen 40 per cent since the much heralded IPO.