people that work at broker dealers cannot actively trade per sec regs and have to clear everything they buy or sell through compliance so if you have some kid on the trade desk trying to reverse engineer your amazing automated strategy then he'd have to hack your computer. and if you trade manual then obviously the point is moot.
To be specific to the question, I think they can see your positions, orders, P&L, margin, etc. This may or may not be the same as looking at your screen, I guess depending on what you're looking at. When I call my broker (IB) they sometimes see more than I see, for example telling me in which underlyings my margin use is being concentrated.
The answer is yes, if you allow some sort of remote desktop viewing software onto your machine and are in a chat session with the broker rep, and they have the same software, and you give them permission to see your screen by you actively sharing the screen, then yes, they can see it. And they give diddly/squat about your trading screen. So no, they cannot remotely see your screen.
Overnight is correct. One time I had problem with Schwab's platform (Streetsmart Edge), could not make it work in MacBook Pro (but window was fine) after one of those periodic update of their platform. Called their technical support, they had to set up screen share to debug. With Mac, to set up screen share they needed my permission otherwise they could not see my screen.
They can't see your computer screen because that would require you to give them explicit permission and access to use remote access software to view your screen and it would be against the law. Most brokers are not willing to break the law to try and obtain your intellectual property. However, they can very possibly see anything and everything that you do within the trading platform itself and unless their terms and conditions stipulate otherwise you would have to assume they can and will if you have anything of value. Most terms and conditions give the broker permission to do this by hiding it in the clause 'general maintenance and support in the ordinary course of business' which gives them unfettered access to anything you do on their platform, at any time. At the end of the day, the real enemy is not your broker but your own naivety so always be mindful of what is possible and within the law in a highly competitive and exploitative industry.
Some brokers and others that are not brokers have the ability to remotely access your screen if you call them with a technical problem about their software. They will tell you they're send you an email with a link in which you must click on it to enable remote access. Also, depending upon your virus/malware protection...you must allow the connection if you get a warning about the link. Remember, in those situations, you called them about a technical problem with their broker trade execution platform and then they told you they will send you an email with a link for you to click on to allow remote access. Yet, they are not doing that to "backtest your strategies" in an effort to steal your genius. After they fix your technical problems...put the link in your virus/malware quarantine file to ensure its disable and they can not access your computer again. Next, run a complete deep scan via your virus/malware protection software to ensure they didn't leave behind some malicious code. What if you didn't call them and gave them permission to remotely connect to your computer screen ? Make it a habit to not open nor click on any links in emails on the computer that stores your trading system. That implies you do all your email reading and other internet stuff on a 2nd computer that you do not trade from or review emails via your mobile device that you do not use for trading purposes. I've have read online of individuals (they are not brokers but are just hackers) that admit or brag about sending out emails via another identity so that if you open their emails they can "watch you in real-time" if you open their emails so that they can perversely watch you like a voyeur/creepy pervert via your webcam. Yet, there's ways to catch them and prevent such from happening: https://nordvpn.com/blog/tell-if-laptop-camera-hacked/ https://www.cloudwards.net/how-to-secure-your-webcam/ https://surfshark.com/blog/is-your-webcam-hacked Yet, they were not brokers. They were just some creepy pervert that tries to impersonate others that you do know so that they hope you'll allow the malware to sneak onto your computer after opening their emails. Simply, they're not backtesting your trade setups and are most likely satisfying some creepy pleasure they have about you. wrbtrader