Actress Emma Watson (C) poses with fellow cast members Daniel Radcliffe and Rupert Grint (L) as they arrive for the world premiere of "Harry Potter and the Deathly Hallows: Part 2" at Trafalgar Square in London July 7, 2011.[Photo/Agencies]

LOS ANGELES?- Harry Potter finished his Hogwarts school days with box-office highs around the world. The question is whether the young wizard can continue to work his charms on audiences now that so many fans already have seen his big-screen finale.

When a film opens to colossal numbers such as the record $169.2 million weekend domestically for "Harry Potter and the Deathly Hallows: Part 2," it usually has nowhere to go but down — and sharply — in its second weekend.

"Conventional wisdom is the bigger they open, the harder they fall," said Paul Dergarabedian, an analyst for box-office tracker Hollywood.com. "There's no way they can sustain it."

Still, distributor Warner Bros. predicts the finale will easily top $1 billion worldwide, joining only a handful of films that have reached that level.

The film is almost halfway there already. Adding in its record international income of $312.3 million, "Deathly Hallows: Part 2" was closing in on $500 million after just days in release.

Domestic revenues for the last three of the seven earlier "Harry Potter" films fell about 60 percent in their second weekends, a steep drop but typical of many blockbusters that count on opening weekend for a huge portion of their total income.

Because of its record launch, the finale could drop even further, down as much as 65 to 70 percent next weekend, said Dan Fellman, head of domestic distribution at Warner Bros. After that, Fellman expects it to settle in for a long run, drawing repeat business from fans and even luring those who have not come out for earlier "Harry Potter" flicks.

"One thing I can tell you about the 'Potter' movies is that the pictures are very front-loaded," Fellman said. "But this is different because, one, it's so well-reviewed, and two, it's the last one in the series. And you can see this movie if you haven't seen the others and still appreciate it."

Opening weekends for the past "Harry Potter" films varied widely, from $77.1 million for 2007's "Harry Potter and the Order of the Phoenix" to $125 million for "Deathly Hallows: Part 1" last fall. Yet the films have played out consistently in the long haul, their total domestic earnings ranging from about $250 million to $317 million.

"Deathly Hallows: Part 2" is virtually certain to shoot past those levels and become the franchise's top earner, no matter how big a drop it takes next weekend, when it faces fresh competition from Paramount Pictures' superhero tale "Captain America: The First Avenger."

Of the $295 million total for "Deathly Hallows: Part 1," 42.4 percent came from opening weekend, according to Hollywood.com. If "Deathly Hallows: Part 2" matched that, it would finish at about $400 million, potentially becoming the first in the series to pass that rare benchmark.

Only 11 films have ever reached that level in the U.S., including "Avatar" at $760.5 million, "Titanic" at $600.8 million and "The Dark Knight" at $533.3 million.

"The Dark Knight" was the previous record-holder for opening weekends with a $158.4 million debut, though factoring in today's higher admission prices, it sold more tickets than "Deathly Hallows: Part 2."

Wildly acclaimed by critics, "The Dark Knight" held up better in subsequent weekends than most of Hollywood's biggest debuts. The film's domestic revenue slipped only 53 percent in its second weekend, while opening weekend accounted for just 29.7 percent of its total.

Like the recent "Harry Potter" films, Hollywood's other top debuts took sharp drops in their second weekends. Revenues for 2007's "Spider-Man 3" fell 62 percent in the second weekend, with the opening weekend accounting for 44.9 percent of total domestic income of $336.5 million. Earnings for 2009's "The Twilight Saga: New Moon" dropped a whopping 70 percent in the second weekend, with the first weekend's business amounting to nearly half of its $296.6 million total.

All-time box-office champ "Avatar" went the opposite route. It started with a big but unremarkable $77 million domestic debut weekend in December 2009. Its revenue the second weekend dropped a tiny 2 percent, while the opening weekend accounted for barely 10 percent of its eventual domestic total.

The top 20 movies at U.S. and Canadian theaters Friday through Sunday, followed by distribution studio, gross, number of theater locations, average receipts per location, total gross and number of weeks in release, as compiled Monday by Hollywood.com are:

1. "Harry Potter and the Deathly Hallows: Part 2," Warner Bros., $169,189,427, 4,375 locations, $38,672 average, $169,189,427, one week.

2. "Transformers: Dark of the Moon," Paramount, $21,328,545, 3,917 locations, $5,445 average, $302,878,797, three weeks.

3. "Horrible Bosses," Warner Bros., $17,777,464, 3,134 locations, $5,672 average, $60,149,603, two weeks.

4. "Zookeeper," Sony, $12,330,512, 3,482 locations, $3,541 average, $42,382,978, two weeks.

5. "Cars 2," Disney, $8,407,529, 3,249 locations, $2,588 average, $165,389,754, four weeks.

6. "Winnie the Pooh," Disney, $7,857,076, 2,405 locations, $3,267 average, $7,857,076, one week.

7. "Bad Teacher," Sony, $5,152,447, 2,659 locations, $1,938 average, $88,457,639, four weeks.

8. "Larry Crowne," Universal, $2,664,550, 2,287 locations, $1,165 average, $31,719,560, three weeks.

9. "Super 8," Paramount, $1,970,377, 1,459 locations, $1,350 average, $122,287,359, six weeks.

10. "Midnight in Paris," Sony Pictures Classics, $1,876,588, 706 locations, $2,658 average, $41,778,698, nine weeks.

11. "Bridesmaids," Universal, $1,722,205, 872 locations, $1,975 average, $161,329,580, 10 weeks.

12. "Mr. Popper's Penguins," Fox, $1,368,355, 1,002 locations, $1,366 average, $61,473,016, five weeks.

13. "Green Lantern," Warner Bros., $1,359,133, 973 locations, $1,397 average, $112,789,166, five weeks.

14. "Monte Carlo," Fox, $1,318,448, 1,169 locations, $1,128 average, $20,110,471, three weeks.

15. "Zindagi Na Milegi Dobara," Eros, $960,548, 100 locations, $9,605 average, $960,548, one week.

16. "X-Men: First Class," Fox, $635,586, 470 locations, $1,352 average, $143,455,857, seven weeks.

17. "The Tree of Life," Fox Searchlight, $626,723, 235 locations, $2,667 average, $10,090,489, eight weeks.

18. "The Hangover Part II," Warner Bros., $504,803, 455 locations, $1,109 average, $251,881,953, eight weeks.

19. "Pirates of the Caribbean: On Stranger Tides," Disney, $493,155, 373 locations, $1,322 average, $237,353,634, nine weeks.

20. "Kung Fu Panda 2," Paramount, $460,755, 354 locations, $1,302 average, $160,074,529, eight weeks.