Here are three of the week's top pieces of financial insights, gathered from around the web:

Tesla beats the shorts
Tesla's surprising earnings report cost its short sellers an estimated $1.4 billion in one day last week, said Thomas Franck at CNBC. The most heavily shorted stock in the U.S. recorded its best day on Wall Street since 2013, popping almost 17 percent to around $300 per share after unexpectedly reporting a third-quarter profit. The surge wiped out "almost 70 percent of short sellers' year-to-date profit" after the stock had slid 23 percent since the start of 2019. Tesla CEO Elon Musk "has over the years taken to Twitter to do battle against" investors betting heavily against his company. Tesla reported earnings well beyond analysts' expectations and revealed to shareholders it is ahead of schedule with a new factory in Shanghai, as well as its Model Y crossover vehicle.

Rules for a five-hour workday
A German consulting firm says its employees produce "the same level of output for clients" while working only five hours a day, said Eric Morath at The Wall Street Journal. "The 16 employees start work at 8 a.m. and may leave at 1 p.m.," but there are some rules. "Small talk during work hours is discouraged," phones must be kept in backpacks, email is to be checked only twice, and social media is entirely off-limits. Meetings "are scheduled to last no more than 15 minutes." But the firm's managing director says the company was profitable in 2018, with "happier employees" who "deliver better work for clients" than those working 40 hours interrupted with distractions. In 2015, a company in San Diego began a five-hour workday that "was an initial success" but soon felt employees' "passion for the work" started waning.

The allowance debit card
"The piggy bank is so passé — get your kids some plastic," said Kaitlin Mulhere at Money. New debit cards "designed specifically for joint parent and child accounts" are emerging as a solution for those who don't carry the cash on hand for weekly allowances. They're also "a way to show kids how to spend smartly in an increasingly digital world." The products are essentially prepaid debit cards with "integrated apps that help kids track their spending and customizable oversight features for parents." Kids can split allowances into separate buckets for saving, spending, and charity. Most of the offerings also allow for "parent-paid interest, in which parents can set a rate to pay out on their children's savings accounts." Some go as high as 50 percent to "incentivize savings."