DES MOINES – If it seems that giant lottery jackpots have people lining up at convenience stores more frequently, just wait: More big payouts could be coming.

Most attention has been on Powerball jackpots since the game's rules were changed in early 2012 to boost payoffs. On Wednesday, Powerball's estimated $400 million jackpot will be the nation's fifth-largest.

Now organizers of the country's other big lottery, Mega Millions, are planning changes of their own. Although Mega Millions still holds the record for the largest jackpot in U.S. history — a $656 million prize in March 2012 — organizers are hoping to more regularly see huge jackpots by lessening the odds of winning big but upping a player's shot at smaller but still hefty prizes.

"Certainly, we were looking at the fact that changes that Powerball made … definitely favorably impacted the jackpot," said Paula Otto, executive director for the Virginia Lottery and lead director for Mega Millions.

"It's doing what it's supposed to do, which is helping Powerball have bigger jackpots on a pretty consistent basis."

Otto said the move is based on extensive consumer research, but she acknowledges the success of Powerball when it increased its ticket prizes from $1 to $2. Other game changes include boosting the starting jackpot from $12 million to $15 million. The jackpot will also grow by at least $5 million between drawings when no top winner is selected.

The Powerball jackpot, displayed at Dahl’s Foods in Des Moines. At right is store manager Don Mark.

Mega Millions doesn't plan to change its $1 ticket price, but an extra $1 option already in the game will be expanded to allow players to increase their secondary prize total to between $1 million and $5 million, a major increase from $250,000.

Powerball and Mega Millions are sold in 43 states, plus the District of Columbia and the U.S. Virgin Islands. The new Mega Millions game goes into effect for its Oct. 22 drawing.