There are a growing number of signs the bull market in equities is overheating, with indicators of investor complacency and risk-seeking reaching the highest levels since 2007 and 1999.

Why it matters: Those periods of extreme euphoria were followed by market crashes.

What's happening: As of late February, investors already had levered up with a record $814 billion borrowed against their portfolios, according to Financial Industry Regulatory Authority data.

• That's a 49% year-over-year increase, the largest since 2007.
• The prior high was during the dot-com bubble in 1999, WSJ reports.

Watch this space: Professional money managers already have started selling.

• Data from Bank of America show the bank's large institutional clients were net sellers of equities for the fourth straight week last week and hedge funds are starting to join them.

What they're saying: "Last week, as the S&P 500 breached 4000 and our work suggests increasing signs of equity euphoria, BofA Securities clients were net sellers of US stocks," the company's data analytics team said in a note.

• The bank's sell-side indicator rose for the third month in a row to a 10-year high and the closest to a contrarian "Sell" signal since May 2007, analysts noted.
• Further, BofA points out that since March 2020 the average recommended allocation to stocks has risen by more than three times the typical rate following prior bear markets.

Be smart: "Increasingly euphoric sentiment is a key reason for our neutral outlook as the cyclical rebound, vaccine, stimulus, etc. is largely priced into the market."

• "We've found Wall Street's bullishness to be a reliable contrarian indicator."

One level deeper: The Cboe's volatility index fell another 5.3% on Wednesday to 17.16, the lowest it has been since February 2020.

• "This low level continues to suggest complete complacency by investors – so worries over rising rates or rising inflation once again appear to be on the back burner," Kenny Polcari, managing partner at Kace Capital Advisors, says in a note.

Yes, but: Big names like JPMorgan CEO Jamie Dimon are taking the other side of that bet. In his annual letter to shareholders, Dimon argued strong consumer savings, vaccine distribution and the proposed infrastructure plan could lead to a "Goldilocks moment" for the market, replete with sustained growth and slow inflation.

The vacancy rate for regional malls in the U.S. reached a record 11.4% in the first quarter, up from 10.5% in the fourth quarter — the largest increase on record, according to Moody’s Analytics. (CNBC)

Uber admits it has had more riders than drivers lately and announces a $250 million "stimulus" to improve recruitment. (TechCrunch)

Americans have saved 42 cents of every dollar received from their March stimulus checks, according to a survey from the New York Fed. (Bloomberg)

For the first time since the 1990s, the global ­middle class shrank last year, with around 150 million people falling down the socioeconomic ladder, according to a recent Pew Research Center estimate. (Bloomberg)

The man behind the iconic tweet of the Fyre Fest dinner — two limp slices of white cheese on wheat bread with "salad" in a styrofoam container — is teaming up with one of the men who helped organize the infamous festival to sell the tweet as an NFT.

• Because of course, he is.

Details: In an email, Trevor DeHaas tells Axios he's hoping to collect upwards of $80,000 that he'll put toward medical expenses from his daily dialysis and kidney transplant.

What he's saying: "A few weeks ago I saw Jack Dorsey, auctioning off the first tweet ever and at the time it was like 2.25 million. Instantly I thought of my viral tweet from Fyre festival," DeHaas says.

• Dorsey's tweet eventually sold for $2.9 million and has spurred a craze that prompted DeHaas' partner in the sale, rapper Ja Rule, and his company Flipkick to sell a Fyre Fest painting for $122,000 last month.
• "Now a few weeks before the 4 year anniversary of the festival (4/28) I’m selling the most iconic cheese sandwich on the blockchain along with the ownership of copyright."

Why it matters: Non-fungible tokens have become the investment world's newest craze, delivering six-, seven- and eight-figure paydays to the creators of images, video clips and tweets that are documented on blockchain and sold to the highest bidder.

• Bridge Oracle CEO Sina Estavi, who paid the $2.9 million for Dorsey's tweet and shelled out another $1.1 million for an Elon Musk tweet, said he did so "to emphasize the importance of NFTs on [the] future of crypto and tech sphere."
• In addition, “I wanted to encourage involving in charities in the crypto space,” he said.

The big picture: "The biggest bubble [in the market] is NFTs because it's new and it's real, in the sense that real money is pouring into it," hedge fund manager and angel investor Howard Lindzon told me last month on the "Voices of Wall Street" podcast.

• "But the markets are not developed yet. ... The digital bubble is NFTs themselves. That doesn't mean it can't go on for four more years," Lindzon, co-founder of StockTwits and CEO of Social Leverage Acquisition, added.
• NFTs also are "the biggest opportunity."

Axios' Jacob Knutsen writes: One big difference between 2021 and 2009: Many of the world's top economic officials this time around are women.

The big picture: Treasury Secretary Janet Yellen, Commerce Secretary Gina Raimondo and U.S. Trade Representative Katherine Tai are front and center on U.S. efforts, Reuters reports.

• The European Central Bank is led by Christine Lagarde, the IMF by Kristalina Georgieva and the WTO by Ngozi Okonjo-Iweala.
• "[W]omen [run] finance ministries in 16 countries, and 14 of the world’s central banks," per Reuters.

Between the lines: The pandemic shattered decades of economic progress for women, and there is concern that the scarring in the labor market could be permanent, Axios managing editor for business Aja Whitaker-Moore says.

• Gender and racial diversity within Biden’s economic policy team likely mean more attention will be paid to issues of inequality across the board.
• That includes policies that will help maximize women in the labor force, ensuring that they earn more and can therefore contribute more to increased economic growth.

The bottom line: UN adviser Eric LeCompte told Reuters he's been "meeting with Treasury secretaries for 20 years, and their talking points have been entirely different."

• "In every area we discussed, Yellen put an emphasis on empathy, and the impact of policies on vulnerable communities.”