Incumbency is definitely paying off in several top House races.

With the filing of first-quarter campaign finance reports this week, it is clear that several targeted House incumbents have bought themselves a measure of political protection simply by outhustling their challengers on the fundraising front.

In New York’s 20th district, for example, freshman Rep. Kirsten Gillibrand (D) finished March with more than $2.4 million in her campaign account after raising $604,000 in the first three months of the year.

That puts Gillibrand well ahead of her highly touted opponent, former New York Secretary of State Sandy Treadwell (R), who finished the quarter with a solid $929,000 on hand, thanks to almost $1 million in personal contributions since he entered the race last year.

Republican incumbents, too, can boast of an advantage in certain races. In Illinois’ 10th district, where Rep. Mark Kirk (R) is facing a rematch with business consultant Dan Seals (D), the incumbent banked more than $2.2 million as of March 31 on the strength of a $644,000 fundraising quarter. Seals, no fundraising slouch himself, finished March with $745,000 on hand after collecting $517,000 since Jan. 17.

Money isn’t a sure harbinger of electoral success, of course — sometimes it’s hard for candidates to overcome certain political dynamics no matter how much cash they have socked away. But an incumbent’s robust bottom line can prove dispiriting even to the strongest of challengers.

Among the other potentially vulnerable House Members who are in a strong position financially are Rep. Gabrielle Giffords (D-Ariz.), who banked almost $1.7 million — even as her challenger, state Senate President Tim Bee (R) was matching her in fundraising for the quarter; Rep. Joe Knollenberg (R-Mich.); and Rep. Jim Marshall (D-Ga.), who had almost three times as much on hand as his well-regarded challengers.

Not every vulnerable incumbent is in such strong shape, however. In New York’s 29th district, Rep. Randy Kuhl (R) finished the first quarter with $200,000 less on hand than his challenger, Democrat Eric Massa. Massa finished the period with $565,000 on hand after raising $278,000; Kuhl had $366,000 in the bank after raising just $112,000.

Other vulnerable incumbents are doing well in the fundraising department but still find their challengers matching or even surpassing them.

In Connecticut’s 4th district, Rep. Christopher Shays (R), a perpetual Democratic target, raised $454,000 and banked $1,138,000. But Democrat Jim Himes raised $429,000 and banked $1,105,000.

In Missouri’s 6th district, Rep. Sam Graves (R) raised $410,000 and reported more than $1.1 million on hand. But Kansas City Mayor Kay Barnes (D) was not far behind, taking in $402,000 and banking $954,000.

Jason Klindt, a Graves spokesman, was quick to criticize the source of Barnes’ take.

“She raised twice as much money from twice as many donors in the 5th district as she did in the 6th district,” he said. “Why should downtown Kansas City get two representatives to Congress when everyone else only has one?”

Meanwhile, in Washington’s 8th district, Rep. Dave Reichert (R) raised $331,000 and banked $698,000, but former Microsoft executive Darcy Burner (D), who is seeking a rematch, took in $522,000 and finished with $922,000 on hand.

Matthew Murray contributed to this report.