Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of real estate investment trust Getty Realty (NYSE: GTY) plummeted more than 20% on Wednesday after being informed by the management of Lukoil North America, LLC that OAO LUKoil had transferred its interest in Getty Petroleum to an unrelated party.

So what: Getty Petroleum happens to be Getty Realty's largest tenant and accounts for more than half of its revenue, so investors are naturally worried about what the move means for Getty Realty going forward. Wall Street analyst JPMorgan went so far as to say that this news is "not a good sign," downgrading Getty Realty on the chances that the new ownership group will look to rework its leases.

Now what: There's simply too much uncertainty for me to jump into the stock right now. With Getty Petroleum representing such a big part of Getty Realty's business, it's tough to say that this 20%-plus plunge is an overreaction from Mr. Market. While things might actually work out fine for the company, there's just not enough detail in today's press release to make a prudent bet, at this point.

Interested in more info on Getty Realty? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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