McDonald's Corp. temporarily closed its headquarters for the third year in a row Wednesday as wage protests targeted the giant fast-food chain's annual meeting.

McDonald's has encouraged headquarters employees to work from home this week, spokeswoman Lisa McComb said in an email. The company will host the annual shareholder meeting at its campus in Oak Brook, Illinois, on Thursday, with security personnel in attendance as usual, McComb said.

Workers from McDonald's and other restaurant chains are pushing for $15 hourly wages and the right to form a union. Last week, the union-backed Fight for $15 campaign said this year's protest at McDonald's annual meeting will be the biggest yet and run from Wednesday evening through Thursday morning.

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The campaign, begun in 2012, has had a key role in convincing some lawmakers and major employers to boost long-stagnant minimum wages and explore other ways to improve working conditions for the many low-paid Americans whose jobs range from flipping hamburgers to caring for the elderly.

McDonald's in July raised its average pay and began offering paid vacations and other benefits for the roughly 90,000 workers in the U.S. restaurants it operates. Most McDonald's workers, however, are employed by franchisees.

They company's stock is trading near all-time highs, spurred by a profit-boosting turnaround plan that includes all-day breakfast. It closed at $123.20 Wednesday, down 0.61 percent. McDonald's did not immediately comment for this story.

Business owners who oppose pay hikes say the additional expense puts jobs at risk.

Workers argue that well-compensated workers do a better job. That could make a big difference at a fast-food chain, where every second of speed matters.

Data from Reuters were used to report this story.