The fourth and final quarter of 2021 kicks off on Friday, and there are a lot of things to watch as the final three months of the year play out.

Will Walt Disney's (DIS -3.01%) big moves to celebrate its massive Florida resort turning 50 pay off? Can Tesla (TSLA -0.96%) pull off fully autonomous driving for the masses? Will fuboTV (FUBO) make its goal for launching a sportsbook app before the end of the year? Will cryptocurrency wallets at Robinhood Markets (HOOD -1.30%) change the game? Let's take a closer look at these four questions that will weigh on the respective stocks in the fourth quarter. 

A person holds a book. An illustrated thought bubble with a bag of money is above them.

Image source: Getty Images.

1. Walt Disney

Disney World turns 50 on Friday. Golden anniversaries are a big deal, but the House of Mouse is playing on a different level. This will be an 18-month event, but it's not just the rollout of new rides, attractions, and merchandise that will keep investors watching. Disney has introduced new annual passes with a lot of premium add-on features that weren't there before. 

A big potential moneymaker for Disney World -- and Disneyland, too -- is a new option where folks can pay for access to expedited queues. Theme park fans may not like the new toll booths, but time is money for many Disney World visitors. The new Genie+ and Lightning Lane premium features should roll out early in the fourth quarter, and if they take off, the media giant's theme parks segment is going to become an even bigger contributor to the well-diversified entertainment empire. 

2. Tesla

The push for self-driving cars inched closer to reality for Tesla over the weekend. It activated a button for all drivers who have paid as much as $10,000 -- or subscribed at a price point of $199 a month -- for access to Full-Self Driving to apply for participation in the beta program. 

Tesla has put a lot of time and effort into autonomous driving, and a successful expansion of the program is key to justifying the stock's hefty industry valuation premium. The realization of Full-Self Driving will be huge for Tesla, but there's a speed bump it will need to navigate carefully.

Tesla also introduced Safety Score over the weekend, a way for it to gauge the forward collision warnings, hard braking, aggressive turning, unsafe following, and forced autopilot disengagements of beta program applicants. One can argue that it's the most unsafe drivers who need self-driving rides the most, but Tesla wants to limit the next wave of participants to folks who aren't so aggressive on the open road. The move makes sense in theory, but will it open the door for folks who paid as much as $10,000 to ask for refunds if they're not accepted in a timely manner to the program? There's never a dull moment with Tesla.  

3. fuboTV

No one is growing faster than fuboTV among the live-TV streaming services. Revenue nearly tripled in its latest quarter. fuboTV has tried to differentiate itself from the competition by positioning itself as a "sports first" platform with more than three dozen channels dedicated to live sporting events, and the biggest step in that distinction will come later this year when it rolls out its own sportsbook app.

The service recently introduced free-to-play predictive games where viewers win prizes for beating other viewers in guessing in-game outcomes. Now it's time to make things interesting. The sportsbook app will let users place real-money bets on the games they are watching. There are legal hurdles to clear in different states, so it may not be available everywhere when it launches as expected in the fourth quarter. However with its core of diehard sports fans you can't ask for a more receptive audience for a new offering that will immediately move the needle.  

4. Robinhood Markets

The fast-growing trading platform that ushered in the era of commission-free trading has been a flurry of activity since going public this summer. Most of its business -- surprisingly enough -- isn't coming from stock trading. Revenue from stock transactions accounts for less than 10% of its business. Options and cryptocurrency trading are the real drivers here, and the latter is also a surprise since Robinhood only currently offers seven different crypto denominations on its platform.

Robinhood also doesn't let its users move their crypto, so it's basically parked on the platform for appreciation potential until they cash out. Robinhood users can't use the crypto to make direct purchases or settle other transactions. They also can't move it to another exchange to take advantage of staking, lending, or other income-generating strategies. Things are about to change for the better.

Robinhood announced last week that it's launching crypto wallets, finally giving its users the freedom to use digital currency as they please. It was a glaring blindspot in Robinhood's cryptocurrency strategy. It should launch in the fourth quarter.