Democrats are facing an uphill battle to keep control of the Senate, but new fundraising reports show they are building up an early cash advantage for the fight. 

Fundraising bursts have helped Democrats win tough races in recent years, with donors opening up their wallets after Donald Trump’s presidential election win in 2016 and fueling a “green wave” to boost Democratic candidates. 

That green wave is building once again, according to fundraising reports covering the first three months of the year, which were filed Monday with the Federal Election Commission. 

But it remains to be seen whether the money can carry Democrats to victory in a year in which they’re on defense in some GOP-leaning states. Republicans need a net gain of just one or two seats to take control of the Senate, depending on which party wins the White House, since the vice president casts tie-breaking votes in the Senate.  

Here are three takeaways from the fundraising reports in Senate races that the Cook Political Report with Amy Walter rates as competitive:

1. Democrats are stockpiling cash …

In the 10 states with competitive Senate races, Democrats are stockpiling millions of dollars ahead of November. 

Per an NBC News analysis of candidates who raised more than $50,000 in the first quarter, Democrats in those 10 races ended the quarter with a combined $100 million in their campaign accounts — more than twice as much as the Republican candidates, who had a combined $42.5 million on hand. 

Democrats ended the quarter with more cash on hand than their GOP opponents in all but one of the competitive races. Only Florida GOP Sen. Rick Scott had more money in his campaign account than his likely Democratic opponent, besting former Rep. Debbie Mucarsel-Powell by $1 million. 

Ohio Sen. Sherrod Brown, one of two Democrats running for re-election in a state that Trump won, ended the quarter with the largest war chest, banking away $16 million. His GOP opponent, businessman Bernie Moreno, had $1.8 million in his account after winning a competitive primary last month. 

Five other Democratic candidates ended the quarter with more than $10 million in their campaign accounts: Sens. Jacky Rosen of Nevada, Jon Tester of Montana, Bob Casey of Pennsylvania and Tammy Baldwin of Wisconsin, and a nonincumbent: Rep. Colin Allred of Texas, who is raising major money online as he runs against GOP Sen. Ted Cruz.

Democrats also outraised their GOP opponents in each competitive race except for Wisconsin, where wealthy businessman Eric Hovde’s $8 million loan to his campaign boosted his fundraising number over Baldwin, putting his total raised at $9.1 million while Baldwin raised $5.4 million. All of Baldwin’s fundraising came from other donors.

2. … and Democrats are largely outspending GOP opponents

Not only have Democrats been outraising their GOP challengers and building up their cash reserves, but the new reports also show that they’re now largely outspending their Republican opponents. 

That early spending has helped Democrats in past election cycles, as they try to define themselves with voters early in the campaign and inoculate themselves from future GOP attacks. But like other campaign finance trends, they offer no guarantee in terms of results.

Across the 10 battlegrounds, Democrats spent a combined $65.7 million in the first quarter to Republicans’ $30.3 million