The S&P 500 hit a curious milestone earlier this month: Less than 10% of its market capitalization was made up of financial services companies. That ratio was as high as 22% in 2007, before the 2008 financial crisis.

Why it matters: This is not a financial crisis. America's banks are well capitalized, the Fed has restored liquidity to the markets, and trust in the financial sector is hitting new highs. Still, banks are severely underperforming the stock-market recovery.

Never has the stock market seen so much gambling. Volume is at record highs, with individual stocks and the market as a whole feeling almost manic. More people than ever are betting more money than ever on which way stocks will move, in a frenzy that feels more like a casino than a safe place for long-term capital appreciation.

Why it matters: Legendary value investor Ben Graham said that in the short term, the market is a voting machine, but that in the long term it's a weighing machine. Right now there is no shortage of votes, but few people believe that the weight readings are remotely reliable.

Both Congress and the Nasdaq this week made it harder for Chinese companies to list their stocks in the U.S. Dan digs in with Alexandra Stevenson, a Hong Kong-based business reporter with the New York Times.

Go deeper: Luckin Coffee faces delisting after admitting fraud

Luckin Coffee (Nasdaq: LK), the Chinese coffee shop chain that recently fired its CEO and COO for falsifying sales data, yesterday received a delisting notice from Nasdaq. One source says that Luckin didn't sufficiently answer questions Nasdaq had asked.

Why it matters: This comes against the backdrop of Nasdaq tightening its listing standards for closely held companies and those that aren't sufficiently transparent about their accounting. It didn't explicitly cite Chinese issuers like Luckin, but its targets were clear.

New research shows retail investors are also moved to make stock purchases by ads they see on TV.

What it means: In a new paper, researchers at Cornell and Hong Kong University of Science and Technology find a "predictable, recurring, and robust pattern between investor exposure to television commercials and subsequent retail stock trading."

Biotech company Moderna had a day for the ages on Monday and finished by announcing the issue of $1.34 billion of new stock at a hefty price.

What happened: A small number of healthy patients given the first doses of Moderna's coronavirus vaccine appeared to have generated antibody responses to the virus, according to early phase one trial data released by the company Monday.

Vroom, a New York City-based online marketplace for used cars, has filed to go public on the Nasdaq under the ticket symbol "VRM."

Why it matters: Vroom's move comes at a time when many other tech companies are holding off on their big public market debut.

The stock market closed up more than 3% on Monday — the biggest rally in over a month — amid news that Moderna's phase one coronavirus vaccine trial showed a positive first step.

Why it matters: The stock market has rebounded in recent weeks in the face of the coronavirus crisis, which has pushed the U.S. economy into the worst downturn since the Great Depression. Long-time investors have warned about stocks' high valuations based on optimism about a vaccine or cure, as well as the economy's ability to fully rebound.

Website builder Wix saw its stock price jump by nearly 7% on Friday after reporting strong earnings, showing that the coronavirus pandemic is increasing demand for its products.

Why it matters: The earnings report shows you can add website building tools to the list of sectors that are seeing benefits from the virus and could indicate a new area of long-term growth.

Fitch is expecting to cut the ratings on a record high number of companies this year as the pace of downgrades has "dramatically increased, owing to the economic crisis caused by the coronavirus pandemic," analysts note in a recent report.

The state of play: After just 58 downgrades in the first 10 weeks of 2020, there have been an additional 347 corporate and financial institution issuers downgraded for a total of 405 through the end of April.