Whew. Talk about a busy Monday. 

Investor optimism linked to Donald Trump's decision to sign a bill that funds the government until Feb. 15 faded in the wake of comments he made during an interview with The Wall Street Journal, as well as on social media, that he may double-down on his demand for $5.7 billion in border wall funding when talks between lawmakers resume this week.

"I personally think it's less than 50-50, but you have a lot of very good people on that board," Trump told the Journal when asked about the chances for a longer-term government funding bill, adding that another shutdown next month was "certainly an option."

At the close, the Dow Jones Industrial Average dropped 209 points, or 0.84%, to 24,528, the S&P 500 fell 0.8%, and the Nasdaq tumbled 1.1%.

What Shark Tank's Kevin O'Leary's Watching in the Markets

Kevin O'Leary, star of ABC's Shark Tank and Chair of O'Shares ETFs, sat down with Daniela Cambone of Kitco News.

"My new theme for 2019-2020 is balance sheet, it doesn't matter which sector you are talking about, you want the best balance sheet in each sector," said O'Leary said, adding that it is more relevant now than the last three years.

"This year owning the boring Pfizers and all that stuff with great balance sheets is where you can hide in the weeds and maybe make 5-6 percent," he explained. "There is a lot of garbage in the S&P right now in terms of low quality balance sheets."

Caterpillar's Down Day

After missing earnings expectations, Caterpillar (CAT) - Get Report had a rough day in the markets. 

Caterpillar is Real Money's stock of the day

The stock cratered on Monday, marking its largest one-day decline in a decade, reported Real Money's Kevin Curran.

The company reported its first earnings miss since 2016, and the miss on earnings per share was the largest reported in 10 years. 

On an earnings call with analysts, CFO Andrew Bonfeld blamed rising freight costs, trade war troubles, and a slowdown in Latin America for the earnings miss and lowered guidance.

Sallie Krawcheck Tackles Tough Issues

Sallie Krawcheck, who was CFO at Citigroup and CEO of Merrill Lynch, left Wall Street to become the CEO of Ellevest--an investing platform designed for women and has been campaigning for diversity ever since.

While Wall Street is no stranger to diversity initiatives, Krawcheck said that "diversity is heading sideways," meaning corporate America still has a long way to go.

"So we infantilize women when it comes to money, which leads us to not knowing what kind of raise to ask for, because we don't talk to anybody about it. And being unprepared for retirement. It's really a tragedy," Krawcheck told TheStreet.

Watch the full interview to see what she has to say about quotas, Wall Street and what corporate America can do to bring women into the room where it happens.