Gregg, who started the day fourth in chips behind Brent Roberts, Shankar Pillai and Brock Parker, rocketed past all three by the end to bag up 2.78 million heading into Day 4.
Two huge pots near the end of the day helped Gregg grab the big lead, capped by a big bust of Henry Lu with a spade flush after the two got it in with Lu's A♦ Q♥ to Gregg's A♠ Q♣.
The late rush gives Gregg, the 2009 PCA Main Event runner-up, a huge 1-million-chip lead over Joseph Wertz, who finished the day in second with 1.75 million.
Day 3 chip leader Roberts was the only one of the Day 3 leaders to make it through the day but he'll have a below average stack of 592,000 to start Day 4.
Pillai busted in 20th and Parker in 24th to both collect $10,403.
Genius28, Polychronopolous Still Alive
While several notable names including Allen Kessler, Vitor Ramdin, Allen Bari and October Niner Russell Thomas got sent to the rail today two notable bracelet winners kept their hopes alive.
Chris "Genius28" Lee, a feared online player who earned his first WSOP bracelet last year, started the day short but finsihed up over 1 million in chips to sit sixth heading into Day 4.
Athanasios Polychronopoulos, who also won his first WSOP bracelet last year, managed to last the day but will start with a below-average stack of 498,000 tomorrow.
Other notables making it to Day 4 include Roberts, Kevin Calenzo and Vinny Pahuja.
Action picks up again from the Parx Casino outside Philadelphia tomorrow at noon ET.
Play down will be to the final tables of six who'll return under the TV lights on Wednesday to vie for the title and $416,127 first-place prize.
Follow the action with the WPT Live Updates team here.
The final 16 playera and chip counts:
1. Anthony Gregg 2,786,000 2. Joseph Wertz 1,753,000 3. Robert Pyne 1,491,000 4. Joseph Couden 1,433,000 5. Stephen Reynolds 1,413,000 6. Chris "Genius28" Lee 1,148,000 7. Tom Miller 998,000 8. Lawrence Sharp 710,000 9. Brent Roberts 592,000 10. Kevin Calenzo 516,000 11.Athanasios Polychronopolous 498,000 12. Chris Vandeursen 480,000 13. Vinny Pahuja 471,000 14. Alan Kraut 276,000 15. Andre Nyffeler 170,000 16. Timothy Chang 142,000Visit www.pokerlistings.com