Log in to MarketBeat.
Browse to your My MarketBeat Watchlist: at the top of your linked watchlist, select the red button
On the Linked Brokerages page, select the red button next to the brokerage you want to unlink.
Your selected brokerage is now unlinked.
OPTIONAL: To also delete the watchlist from your watchlists, navigate back to your My MarketBeat page.
Find the appropriate, now unlinked, brokerage account watchlist and select the red button above the watchlist.
A 'DELETE ALL' confirmation page appears.
Populate the confirmation page and select the 'DELETE ALL' button.
Your linked brokerage is now both unlinked and deleted from your watchlists.
Repeat steps 1-8 for additional brokerages.