Groups backing Sen. Ted Cruz (R-Tex.) say they have raised $31 million this week in support of his 2016 bid. (Andrew Harnik/AP)

GOP presidential candidate Ted Cruz vaulted to the top tier of the 2016 money race Wednesday as supporters announced that super PACs backing his bid had raised $31 million in a single week.

The haul — which ranks as one of the biggest fundraising surges in modern presidential-race history — served as a sudden wake-up call for the rest of the likely Republican field, particularly Jeb Bush, who until now had enjoyed his status as the premier fundraiser in the contest’s early stage.

The influx of funds comes amid a string of successes for the first-term Texas senator, who announced his candidacy to fanfare last week and ranks just behind Bush in the latest polls. Cruz, 44, has quickly become one of the hard-right’s favorites in early primary and caucus states while leaping ahead of his conservative rivals with his launch.

Quite a few Republican veterans view Cruz, who helped instigate the 2013 federal government shutdown, as a wily gadfly with limited appeal to a broader electorate. But the prolific fundraising over the past two weeks suggests Cruz is running not as a longshot ideologue, but rather as a serious contender for the GOP nomination.

The Cruz fundraising also underscores the extent to which multimillionaire and billionaire donors are influencing the Republican race, where unlimited donations to super PACs are the rule and seven-figure checks have become routine.

So far, Cruz is surprising many — including himself, he said on the stump last week in Iowa. Cruz’s own campaign raised
$4 million during its first eight days, mainly relying on
small-dollar donations.

Dathan Voelter, an Austin-based accountant and attorney who is a close friend of Cruz, said Wednesday that four super PACs set up to back Cruz will take in $31 million by the end of this week; the figure was first reported by Bloomberg News. Operating under numbered versions of the name “Keep the Promise,” the committees submitted paperwork to the Federal Election Commission on Monday.

“Our goal is to guarantee Senator Cruz can compete against any candidate,” Voelter said in a statement, calling the arrangement of the super PACs a “powerful vehicle” that can “provide the appropriate air cover in the battle.”

Bush associates said that while they are impressed by Cruz’s ability to draw heavy-hitting donors, they believe the former Florida governor is better positioned to survive what could be a lengthy campaign.

“If Cruz can raise $30 million, okay, good, but at the end of the day, this is a marathon, not a sprint,” said former Pennsylvania governor Tom Ridge, a Bush supporter. “In time, the field will narrow.”

Cruz, a graduate of Harvard Law School and Princeton University, is best known as a tea party rabble-rouser, but he has also cultivated relationships with prominent Republican donors and has a level of comfort with Wall Street.

Sen. Ted Cruz has declared his candidacy for president. The Texas Republican is known for his fiery oratorial style. Here's his take on immigration, Obamacare and, well, green eggs and ham. (Gillian Brockell/The Washington Post)

Cruz is married to an on-leave Goldman Sachs managing director and lives with his family in a high-rise condo in Houston. He spent the past year meeting with private-equity titans and moguls in New York, California and Florida. In January, he appeared at an enclave in Palm Springs, Calif., hosted by David and Charles Koch.

According to his advisers, Cruz’s argument to GOP donors in those sessions is that the Republican Party has stumbled in the past two presidential campaigns because it did not get enough conservatives to the polls. To get those voters off the sidelines, he believes the party should lurch to the right rather than the center.

Cruz’s pitch contrasts with the arguments of several others in the field, including Bush, who is expected to announce his run later this spring; Sen. Rand Paul (R-Ky.), who launched his campaign Tuesday; and Sen. Marco Rubio (R-Fla.), who is slated to formally enter the race Monday in Miami. All three say the party should expand by reaching out to voters who have not been in step with GOP hard-liners, whether on immigration, education or foreign policy.

Cruz is in the middle of a 10-city fundraising blitz this month. He held an event in Austin on Monday and attended a fundraising dinner in San ­Diego on Tuesday.

Cruz’s donor network is extensive, with hotbeds of support in Texas and New York. Last month, after announcing his campaign to thousands of young Christians at Liberty University in Lynchburg, Va., Cruz was hosted in Manhattan by Rebekah Mercer, daughter of hedge-fund manager Robert Mercer.

GOP pollster Kellyanne Conway, who was at the Mercer reception, said Cruz was well-
received by the conservative crowd, which included New York businessman John Catsimatidis and CNBC personality Larry ­Kudlow.

“He was in the belly of the beast, gave remarks and took questions,” Conway said. “Anyone who says he’s the tea party candidate is completely misreading him. That label is meant to be a slight, and it doesn’t capture his actual reach.”

But Rep. Peter T. King (R-N.Y.), a frequent Cruz critic, was incredulous that rich Republicans would devote parts of their fortunes to the Texan. “Honestly, I don’t know,” he said in an interview. “I can’t see him winning. The only thing Cruz will use that money for is dividing the party.”

According to the Center for Responsive Politics, which tracks FEC data, Cruz in recent years has raised more than $700,000 from the Club for Growth, a conservative advocacy group; nearly $70,000 from Goldman Sachs employees; and thousands more from other financial firms, including Credit Suisse and Berkshire Hathaway.

Cruz’s campaign made its first ad buys of the cycle this past weekend, purchasing national time during “Killing Jesus” on Fox News and ads in four primary states during NBC’s “A.D.: The Bible Continues.”

Federal law prohibits federal officeholders from directing or soliciting money for their would-be super PACs. No such restrictions exist for governors or others until they become federal candidates, providing an incentive for hopefuls such as Bush and Gov. Scott Walker (R-Wis.) to delay an official entry into the race.

Bush especially has been encouraging donations to the “Right to Rise” super PAC since he began to explore a campaign late last year. Some of his boosters, dubbing Bush’s efforts “shock and awe,” have suggested that his allied super PAC could raise up to $100 million by summer — a prediction Bush’s aides have downplayed.

Most other potential Republican candidates have seen their supporters form independent groups to help them. A super PAC called America Leads, which plans to back Gov. Chris Christie of New Jersey, was announced last month. Walker’s Our American Revival, registered under section 527 of the tax code, has been promoting him as he makes his political travels.

Zezima reported from Manchester, N.H.

Zezima reported from Manchester, N.H.