Apple’s senior staff had a busy — and profitable — trading day Thursday.

More than a million restricted shares of Apple (AAPL) stock that seven of them were granted on Dec. 14, 2005 became fully vested Wednesday. The next day, with Apple opening at an all-time record high, four of them sold off all those shares pursuant, as the SEC Form 4 has it, to a Rule 10b5-1 trading plan.

COO Tim Cook, who two weeks earlier was given a $5 million bonus and stock options worth $17 million, was the big winner. He sold 300,000 Apple shares at prices ranging from $226.9 to $230.7, for a total of $68.8 million — $32 million of which was set aside for taxes.

When Cook was granted those shares, Apple was selling for $72.01. It opened Thursday at $230.92 and closed, thanks in part to all that selling, $4.57 lower.

Three other officers also dumped their restricted shares Thursday:

• Peter Oppenheimer, CFO: Sold 200,000 shares. Cleared $45.98 million.
• Ron Johnson, SVP for retail: Sold 200,000 shares. Cleared $45.95 million.
• Phil Schiller, SVP for marketing: Sold 150,000 shares. Cleared $34.47 million.

Three other senior staffers — Serlet Bertrand (granted 150,000 restricted shares in 2005), Scott Forstall (50,000) and Robert Mansfield (50,000) — sold some of their shares to satisfy minimum statutory withholding requirements and held on to the rest.

See also:

• Apple’s Tim Cook gets his earthly reward
• Handicapping Apple’s back bench

[Follow Philip Elmer-DeWitt on Twitter @philiped]