Rep. Tom Cotton (R-Ark.) is seriously considering a run against Pryor. The first-term House member is a prodigious fundraiser popular with both the GOP's donor class and its Tea Party base.
Although his second-quarter fundraising haul is a significant dip from his $2 million first-quarter total, the earlier result was buoyed by a $1 million event with former President Clinton.
Begich, meanwhile, has now raised nearly $1 million for two consecutive quarters.
He now has more than $2 million in the bank, money that will go far in Alaska's inexpensive advertising markets.
His seat, as well as Pryor’s, is among three or four up for grabs in 2014 that will determine which party controls the Senate.
Alaska Lt. Gov. Mead Treadwell is the current front-runner for the GOP nomination and 2010 Republican Senate nominee Joe Miller (R) has also announced he is running.
Former Alaska Gov. Sarah Palin (R) has recently said she is considering a Senate run after hearing appeals from supporters to jump into the race.
Among other Democrats facing reelection this cycle, Sens. Kay Hagan (N.C.) and Al Franken (Minn.) both brought in around $2 million in the second quarter.
Sen. Mary Landrieu (La.) raised $1.7 million, Sen. Mark Warner (Va.) raised $1.4 million, Sen. Mark Udall (Colo.) raised $1.3 million and Sen. Jeanne Shaheen (N.H.) raised $1.2 million.
Democratic candidates making first-time Senate bids posted big numbers as well. Rep. Bruce Braley (Iowa) brought in $1.25 million while Rep. Gary Peters (Mich.) raised $1 million. Both are expected to be their party’s nominees.
Republicans dismissed the significance of the Democrats' brisk fundraising.
"Majorities on the verge of catastrophe have such hubris that they fool themselves into believing that money can solve all of their woes and electoral shortcomings, but ask Republicans how that turned out in 2006 or ex-Speaker Pelosi how it turned out in 2010," said National Republican Senatorial Committee spokesman Brad Dayspring.
"The lone talking point left for Democrats is to throw money at the problem, but one look at the political graveyard shows that alone is failing strategy for a failing majority."