Former New York City Mayor Michael BloombergMichael Rubens BloombergBloomberg: Trump should be impeached Bloomberg releases gun control plan Bloomberg network used widely in finance directs to his campaign site: report MORE (D) topped Sen. Kamala HarrisKamala Devi HarrisCastro hits fundraising threshold for December debate Poll: Majority of voters name TV as primary news source Buttigieg: Harris 'deserves to be under anybody's consideration' for vice president MORE (D-Calif.) in a new Hill-HarrisX poll of the Democratic presidential primary race.

The survey released on Monday found that support for the former mayor ticked up from 3 percent to 6 percent among likely Democratic voters and Democratic-leaning independents. 

Sen. Kamala Harris (D-Calif.), meanwhile, fell behind with 2 percent support, a two-point decrease.

This marks the first Hill-HarrisX poll that has been taken since Bloomberg officially jumped into the 2020 race, though he was included as a possible candidate in a previous survey.

However, Bloomberg still significantly trails the party’s current front-runners, former Vice President Joe BidenJoe BidenTrump to hold campaign rally in Michigan Castro hits fundraising threshold for December debate Buttigieg draws fresh scrutiny, attacks in sprint to Iowa MORE (D), Sens. Elizabeth WarrenElizabeth Ann WarrenTrump to hold campaign rally in Michigan Castro hits fundraising threshold for December debate Buttigieg: Harris 'deserves to be under anybody's consideration' for vice president MORE (D-Mass.) and Bernie SandersBernie SandersTrump to hold campaign rally in Michigan Castro hits fundraising threshold for December debate Buttigieg draws fresh scrutiny, attacks in sprint to Iowa MORE (I-Vt.), and South Bend, Ind., Mayor Pete ButtigiegPeter (Pete) Paul ButtigiegCastro hits fundraising threshold for December debate On The Money: Congress races to beat deadline on shutdown | Trump asks Supreme Court to shield financial records from House Democrats | House passes bill to explicitly ban insider trading NYT editorial board calls on Buttigieg to disclose details of work at consulting firm MORE (D). All four contenders have vied for control of the top tier of the Democratic field for months.

Biden still holds the lead, inching up one percentage point to 31 percent support. His fellow top rivals saw a slight dip, with Sanders dropping 3 points to 15 percent support and Warren sliding 5 percentage points to 10 percent.

Buttigieg, who gained momentum in recent weeks, received 9 percent support, a two-point increase from the prior Nov. 16-Nov. 17 poll.

Businessman Andrew YangAndrew YangCastro hits fundraising threshold for December debate The Hill's 12:30 Report: Pelosi says House will move forward with impeachment Booker: Primary voters 'being denied' their candidates of choice MORE, Amy KlobucharAmy Jean KlobucharCastro hits fundraising threshold for December debate Klobuchar lauds power of free press in post about her father The Hill's 12:30 Report: Pelosi says House will move forward with impeachment MORE (D-Minn.) and former Housing and Urban Development Secretary Julián Castro garnered 2 percent.

The rest of the contenders in the crowded Democratic field received 1 percent in support or less. Another 3 percent said they were unsure. 

The survey comes in light of an ever-fluid Democratic primary race.

Though the field recently expanded with the addition of Bloomberg and billionaire Tom SteyerThomas (Tom) Fahr SteyerCastro hits fundraising threshold for December debate The Hill's 12:30 Report: Pelosi says House will move forward with impeachment Booker: Primary voters 'being denied' their candidates of choice MORE, the primary also lost two candidates over the last few days.

Former Rep. Joe Sestak (D-Pa.) and Montana Gov. Steve BullockSteve BullockSteve Bullock exits: Will conservative Democrats follow? Krystal Ball: What Harris's exit means for the other 2020 candidates Trump on Harris dropping out of race: 'We will miss you Kamala!' MORE (D) each ended their 2020 White House bids after failing to gain traction in national polls.

Sestak announced the news in a press release over the weekend, saying he was thankful for what he called an "endeavor filled with immeasurable wisdom, passions, humor and insights to, and from, the people of America."

A day later, Bullock issued a statement announcing his own departure from the 2020 race.

"While the concerns that propelled me to enter in the first place have not changed, I leave this race filled with gratitude and optimism, inspired and energized by the good people I've had the privilege of meeting over the course of the campaign,” he wrote.

The Hill-HarrisX poll surveyed 1,001 registered voters between Nov. 1-Dec. 1. It has a margin of error of plus or minus 3.1 percentage points. 

—Tess Bonn