If you want to outperform the average billionaire, you might try just sticking all your money into an S&P 500 index fund.

Why it matters: While it's true that the ultra-rich have been been getting richer in recent years, even they haven't been able to keep up with the torrid pace set by the U.S. stock market.

• There are exceptions, of course, particularly of late for those with warm ties to Donald Trump. Elon Musk and Peter Thiel, for example, have had a very good year, and Trump's Cabinet will feature plenty of their ultra-rich compatriots.

Between the lines: Though billionaires have effectively unlimited access to the world's top investors and financial strategies, almost nothing can keep up with the sheer power of U.S. stocks when they're on a bull run.

• That's worth keeping in mind when financial services companies try to sell you access to investments that have historically been available only to the ultra-rich.

The big picture: Billionaires face two disadvantages compared to the S&P 500.

• One is that they're global, so they tend to be exposed to global markets, which have generally underperformed U.S. stocks.
• The second is that they tend to be concentrated in their own family companies. Even in America, two out of three S&P 500 companies are underperforming the index as a whole. (Thanks, Nvidia.)

The other side: Billionaires do, however, have the advantage that there are more of them than ever.

• This year's total billionaire wealth of $14 trillion can be attributed to 2,682 billionaires, up more than 50% from 2015, according to a new report from UBS.
• Meanwhile, the number of companies in the S&P 500 is always very close to 500.

By the numbers: The wealth of the average billionaire rose 45% over the nine years between 2015 and 2024, from $3.6 billion to $5.2 billion, per UBS.

• That's a rise of just 8% in real terms, or less than 1% per year.

The bottom line: When you're already dynastically wealthy, you often focus more on preserving your wealth than you do on growing it.

• Those of us saving for retirement, by contrast, generally have a much greater need for our savings to grow.

Child care issues are increasingly keeping parents out of the workforce, finds new research from the Federal Reserve Bank of Chicago.

Why it matters: If parents can't work, that means less income for families and fewer workers for businesses to hire.

• Especially for mothers, lack of access to child care can create long-term career issues, holding parents — typically women — back from promotions, opportunities and advancement.

Between the lines: You'd think that after the pandemic shuttered daycare centers and schools, parents would now have an easier time. Instead, the situation worsened.

How they did it: The researchers looked at Census surveys that ask people why they haven't been working, examining three different periods — pre-pandemic, peak pandemic and post-pandemic from 2022-2024.

• They narrowed in on responses from parents who live with children under 18, and cited child care problems as the main reason they were either not in the labor force, working part-time only or missing work days.

By the numbers: The number of these child care-affected parents increased by 19% from the pre-pandemic period to present day.

• Mothers living with a child under age five were twice as likely to face these problems as those living with older kids, or fathers.

State of play: The report doesn't identify these child care problems, but there are generally two big barriers for parents trying to access care these days.

• Price. The cost of care has spiked post-pandemic. For many families, child care for one child costs about the same as rent, per a new report from the Labor Department that looks at 2022 data.
• Labor shortages. Hiring and turnover is a big issue, as child care is one of the lowest-paying professions in the country.

Zoom out: Child care has typically been a Democratic issue, but as the situation worsens it's increasingly on the GOP radar.

• During his campaign, President-elect Trump said that increased tariffs would take care of the problem. His running mate has proposed raising the child tax credit — something Trump did in his first term — and encouraging more grandparents to look after kids.

The intrigue: Even as child care challenges have increased, more mothers of young children have entered the workforce over the past few years.

• That could indeed be raising demand for care — and making it harder to find.

The big picture: Child care issues are causing headaches for employers, too.

• One reason researchers at the Chicago Fed are looking at child care — they've put out several papers recently — is that they keep hearing about the issue from the business community, says Brianna Smith, a senior research analyst who worked on the report.
• The recurring complaint: Employers are having trouble hiring because potential employees can't find someone to watch their children. "Without even asking people kept bringing it up," Smith says.

Christmas trees get cheaper as Christmas Day approaches — but that doesn't mean shoppers looking to get the best value out of their tree purchase should delay it as long as they can.

Why it matters: The reason for tree prices to decline as Christmas approaches is twofold.

• Firstly, the choicest specimens get snatched up early, leaving only the straggly also-rans.
• And secondly, there's simply less value in having a tree up for a week than there is in living with one for a month or more.

How it works: Lord Darlington tells Cecil Graham in Oscar Wilde's "Lady Windermere's Fan" that a cynic is "a man who knows the price of everything, and the value of nothing."

• To back out the value of a tree, rather than just the price, Axios looked at the amount paid per day of enjoyment, assuming the tree stays up until Jan. 5.

The bottom line: By that metric, the best time to buy a tree is as early as possible.