Sanders' record March haul of almost $46 million topped Clinton by about $19 million. Yet he vaporized that cash advantage by spending roughly $17 million more than she did. Sanders shared the numbers on his campaign website, but his report wasn't available through the FEC by early Thursday.
While racking up wins in recent primary states, except New York this week, Sanders has failed to nudge Clinton off her apparent path to the party's presidential nomination.
She began April with $29 million, and he with $17 million.
On the Republican side, front-runner Donald Trump offered his biggest campaign loan yet: $11.5 million. That made up the bulk of his $13.8 million in March spending, and brought his total personal campaign investment to about $36 million.
Meanwhile, his two GOP rivals struggled to keep pace financially.
Kasich Fails to Launch with Donors
Ohio Governor John Kasich scored a must-win primary in his home state last month, but the victory only modestly helped his campaign coffers. He raised $4.5 million in March, only about $1 million more than the previous month.
That's despite his assertion that he's the most electable Republican in a general election. Donors don't appear to see that as enough of a reason to give.
The main outside group working to help him also fared relatively poorly, filings show. The super PAC New Day for America brought in $2.8 million in March - even less than it raised a month earlier, before his Ohio win.
Six-figure backers included hedge fund manager Stanley Druckenmiller, who gave $400,000. Quicken Loans founder and chairman Dan Gilbert and hedge fund manager David Tepper, president of Appaloosa Management L.P., both gave $250,000.
New Day had $1.2 million cash on hand as this month began, while Kasich's campaign had about $1 million.
Texas Senator Ted Cruz, who was denied any delegates Tuesday in the New York primary, continued to romp Kasich when it comes to fundraising, taking in $12.5 million in March.
Like Kasich, Cruz cannot win the GOP nomination outright; however, he has amassed far more delegates than the governor, putting him in a stronger position if the nominee is chosen this summer at a contested convention.
Cruz's campaign spent almost as much as it brought in last month, largely on television advertisements and prospecting for new donors. Even so, Cruz began April with about $8.8 million cash on hand.
Cruz can also count on a bevy of super PACs that continue to rake in new dollars.
Missouri-based Herzog Contracting Corp, an asphalt and pavement contractor founded by Bill Herzog, donated $1 million, and so did Richard Uihlein, CEO of shipping supply distributor Uline Inc.
In addition, Cruz's top financial supporter, hedge fund billionaire Robert Mercer, ponied up another $2 million in March, bringing his total investment in Cruz's efforts to $13.5 million.
Trusted Leadership and three of the most active groups it is synced with began April with $11.6 million left in the bank, FEC filings show.
Cash Against Trump
Our Principles PAC, a group established solely to oppose Trump's presidential run, brought in about $8.4 million including a $200,000 donation from the Cruz-aligned Keep the Promise super PAC, which is funded by Mercer.
Other six- and seven-figure checks came from hedge fund investors Paul Singer and Cliff Asness, who had backed Marco Rubio's 2016 bid. Cruz supporter Uihlein gave $2 million.
The group was initially funded with a million-dollar investment from the Ricketts family, whose patriarch founded TD Ameritrade. They've now given $4.5 million.
But Our Principles quickly tore through that money, spending more than $11.2 million in March and ending the month with just under $425,000 cash on hand. The group's filing shows that the bulk of the money went into anti-Trump ads, research and voter contact.
What Primary? Clinton Allies Eye November
On the Democratic side, an outside group helping Clinton is looking ahead to the general election, even as Sanders remains in the primary.
Priorities USA, a super PAC that says it plans to pour $125 million into ads supporting Clinton, reported taking in $11.7 million in March, bringing the group's total haul this election cycle to more than $67 million.
So far, data from Kantar Media's advertising tracker show the group has reserved more than $64 million in television ads scheduled to air from Aug. 2 through the day before the general election.
The group also said it will start airing other TV ads in June and plans to spend heavily on digital advertising to support Clinton and attack Cruz and Trump.
At the start of April, Priorities reported more than $44 million cash on hand. A group spokesman also says it has lined up an additional $49 million in "commitments" from wealthy donors.
The Carson Money Train
Ben Carson may have dropped out of the race for president on March 4, but his campaign kept right on paying political consultants.
According to FEC filings, Carson spent $157,000 on political strategy consulting and an additional $103,000 on travel for his political consultants in the weeks after he ended his bid. The campaign also spent an additional $39,000 on travel for various employees and consultants and reported spending on payroll right up until March 31.
The spending continued a trend uncovered last month by The Associated Press. Carson, who raised more than $63 million this election cycle, paid at least $16 million to fundraising and marketing firms owned by a pair of his top consultants, the AP found.
And federal filings show the campaign was still sitting on a considerable amount of cash. At the end of March, Carson America reported $3.4 million in cash on hand. That's more than Kasich, who remains in the race.
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