On today's episode of Catalysts, Yahoo Finance's Seana Smith and Madison Mills break down the biggest stories of the trading day, from the European Central Bank's interest rate decision to the investigation of "Roaring Kitty."

The European Central Bank (ECB) cut interest rates for the first time since 2019, from 4% to 3.75%. Former ECB president Jean-Claude Trichet says the decision "was very much anticipated," adding, "I think they are right to mention the fact that they do not want to be pre-committed to a particular path for the decrease of the interest rates, and frankly speaking, it seems to me very wise because now they have succeeded extremely well from a peak at 10% to go down a lot. And the anchoring of expectations is quite good, so they have to continue to be cautious." TD Bank Global Head of FX & EM Strategy Mark McCormick notes that while many of the G10 central banks have cut rates, the Fed still has not made a move, which could "challenge this Goldilocks environment we're in where FX volatility is very low."

Nvidia (NVDA) is making major news as the chip company will execute a 10-for-1 stock split on Friday after the market close. Option Research & Technology Services Principal Matt Amberson notes that the price of Nvidia's options are "extraordinarily high," so the split will make the options "a lot easier" to trade. Meanwhile, the US Justice Department and the Federal Trade Commission are looking to investigate the company, alongside OpenAI and Microsoft, according to a report from The New York Times. The DOJ investigation will determine whether Nvidia (NVDA) has violated antitrust laws.

Another investigation is underway as the Massachusetts Securities Regulator launched a probe into the trading activity of GameStop (GME) investor Keith Gill, more commonly known as "Roaring Kitty." Defense attorney and former SEC Enforcement Division Chief Lisa Bragan?a explains that regulators will seek information about whether Gill's actions amount to market manipulation, investigating both his public and private conduct.

This post was written by Melanie Riehl