From the Churchill Downs website:
A carryover pool of $686,309 from Churchill Downs’ $2 Pick 6 on Kentucky Derby Day will be split when racing returns Thursday. Half of the pool - $343,154 - will be included in Thursday’s first 20-cent minimum Single 6 Jackpot. Thursday’s Single 6 Jackpot pool requires a mandatory payout, regardless of whether an on-track or simulcast patron selects winners of all six Churchill Downs races included in the wager.
The remaining $343,154 from the Derby Day carryover goes into the Friday, May 13 opening pool of the meet-long Single 6 Jackpot. Single 6 Jackpot rules require that the pool be paid-out only if there is a single winning ticket-holder. If multiple tickets contain six winners, 90 percent of that day’s pool will be paid out and 10 percent will be added to the wager’s carryover. If there are no tickets with six winners, the entire pool is added to the carryover; there are no consolation payouts. Takeout on the 20-cent-minimum Single 6 Jackpot is 15 percent, one of the lowest multi-race wager takeout rates in American racing.