California's proposed billionaire tax is hanging on to a narrow lead as the November election approaches, according to a new poll from the Berkeley Institute of Governmental Studies. The survey, released Friday, shows 48% of likely voters inclined to vote Yes on Proposition 40, while 41% say they'll vote No. That leaves 11% still on the fence, which is a lot of wiggle room in a race this tight.

The measure would slap a one-time 5% tax on certain taxpayers with assets over $1 billion, with the money primarily going to health care. It's a simple idea that's proving anything but simple in practice.

Proposition 40 Holds Narrow Lead

One thing that's not a problem for the measure is awareness. A whopping 72% of likely voters have heard of Proposition 40, which is pretty remarkable for a state ballot initiative. By contrast, only 27% know about the two counter initiatives, Propositions 41 and 42.

The poll, conducted Aug. 3-9, reveals a stark partisan split. Democrats are all in, with 70% supporting the tax. Republicans are almost uniformly against it, with just 12% in favor. Among independents and nonpartisans, it's closer to a toss-up: 50% support, 39% oppose.

The California Democratic Party officially endorsed Proposition 40 earlier this month, despite Gov. Gavin Newsom's opposition. The party's executive board narrowly approved the measure after earlier votes fell short. Newsom has been a vocal critic of the state-level tax, arguing instead for a federal minimum tax on Americans with more than $100 million in assets. It's a classic political dance: support the idea of taxing the rich, but prefer to do it at a level where you don't have to deal with the consequences.

Billionaire Opposition Grows

Speaking of consequences, some of California's wealthiest residents are not thrilled. Alphabet Inc. (GOOGL) co-founder Sergey Brin has come out against the measure and has been putting money into a political advocacy group fighting it. That drew a sharp rebuke from Sen. Bernie Sanders, who pointed out that Brin could face a $14 billion tax bill if the measure passes. Reports cited in the article put Brin's net worth at $260 billion, so it's a significant chunk of change, even for him.

Brin isn't the only one thinking about leaving. Tax adviser David Lesperance said seven wealthy Californians have already packed their bags and left the state ahead of the proposed tax. But not everyone is fleeing. Venture capitalist Chamath Palihapitiya has said he'll stay and pay the tax, which is a refreshing dose of civic commitment.

Startup Concerns Add to Debate

The measure has also sparked worries about California's startup scene. Billionaire entrepreneur Mark Cuban has warned that the tax could discourage investment and push high-value startups and their founders out of the state. He's got a point: startup founders often become "cash poor, stock rich" after their companies hit billion-dollar valuations. A tax on assets, not income, could hit them hard even if they haven't sold a single share.

Cuban argues that investors might start favoring companies outside California if the measure passes, which could have long-term implications for the state's economy. It's a classic tension between taxing wealth and fostering innovation.

Supporters, meanwhile, say the measure would help fund health care, food assistance, and state budget needs. The poll shows the strongest support in Los Angeles County and the San Francisco Bay Area, while opposition is higher in Orange County, the Central Valley, and the North Coast/Sierras region. That's a geographic split that mirrors the state's broader political divide.

The survey included 4,207 registered voters, with 2,310 weighted as likely voters for the November general election. The poll has an estimated sampling error of approximately 2.5 percentage points at the 95% confidence level, so the race is well within the margin of error.

As November approaches, both sides are gearing up for a fight. With nearly half the state behind it and a vocal opposition, Proposition 40 is shaping up to be one of the most closely watched ballot measures in the country.