Travis Kalanick, the founder of Uber who resigned as CEO last summer, is reportedly planning to sell 29 percent of his stake in the company, which will make him about $1.4 billion. What does it mean to come into that kind of wealth? What is the smartest thing to do with the money, and what choices should a person avoid? Rebecca Walser, a wealth management advisor who specializes in financial planning for high net worth individuals, tells CNBC Make It that the return on the sale will go into a brokerage account, where these kinds of stock equity transactions take place, and that it will immediately be taxed as a long term capital gain at the top rate of 20 percent. So, once Kalanick sells his stock in Uber and deals with the IRS, he'll end up with about $1.1 billion. That is essentially cash that he can transfer into a personal bank account. From there, Walser suspects he will keep a significant portion invested in the market. "Everyone is really bullish right now," she says, citing the fact that all three indexes — the DOW, NASDAQ and S&P 500 — are all hitting unprecedented highs. "This is actually a phenomenon ... Psychologically, [people] think they're missing out, and they buy in when the market is hitting these top rates."

That's not always wise, says Walser. "The one conventional wisdom that I believe is 100 percent right is: Buy low, sell high." The market may be overdue for a correction, meaning a slight drop of around 10 percent. She notes, however, that the correction could be put off by the recent tax reform because of its promise to repatriate, or return, several trillion dollars back to companies and thus into the market. Still, she says, Kalanick, and any beneficiary of a windfall, should be cautious. As one California man recently discovered, there are often downsides to receiving a sudden and unexpected fortune. Loren Krytzer went from living on $200 a month to raking in $1.5 million after selling an old family heirloom that turned out to be a Navajo blanket from the 1800s. Now his taxes are higher and family members are bothering him for a cut. It's not as though all of his problems have gone away. In fact, he finds he may have to move to Idaho, where life will be more affordable.