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 Yandex NV (NASDAQ:YNDX) climbed as much as 9.6% early Wednesday, then settled to trade up around 4.3% as of 1:30 p.m. after the Russian Internet search leader announced solid fourth-quarter results and an antitrust complaint against Google.

So what: Quarterly revenue climbed 21% year over year to 14.7 billion Russian rubles ($260.7 million), which translated to adjusted net income of 4.0 billion rubles, or RUR 23.44 ($0.42) per diluted share. Analysts, on average, were expecting slightly higher revenue of RUR 14.74 billion to result in significantly lower earnings of RUR 12.85 per share.

And though Yandex opted not to provide full-year 2015 guidance based on the current macroeconomic situation in Russia, for the current quarter it expects revenue to climb approximately 15% year over year. Analysts were modeling revenue growth of 16.9%.

Now what: The light revenue outlook notwithstanding, Yandex investors were pleased when the company also revealed it has filed an antitrust complaint against Google, which has steadily gained share of the Russian market over the past year by bundling its search engine and apps with Android, which is easily Russia's most popular mobile operating system. But Yandex also claims several smartphone makers told it in 2014 they were no longer able to pre-install Yandex services on their Android devices, putting the company at a distinct competitive disadvantage to Google. Instead, Yandex believes user-centric services should be unbundled from the Android OS to return the Russian market to a more level playing field.

Whether its request succeeds to that end remains to be seen, but it's evident Yandex isn't about to let its core market go without a fight. This is something investors should continue to watch closely. But for now, given its encouraging fourth-quarter results, I think investors are right to bid up Yandex stock today.