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

For stock market investors, Wednesday followed the same general theme as yesterday, with the Dow falling on earnings weakness even as the broader market posted modest gains. Several stocks posted extremely strong gains, though, with Nuance Communications (NUAN), RadioShack (RSHCQ), and Green Dot (GDOT 1.07%) all climbing impressively in Wednesday's session.

Nuance climbed almost 8% after announcing preliminary results for its fiscal first quarter that exceeded its prior guidance by a substantial amount. The voice-recognition specialist expects adjusted revenue of between $487 million and $491 million, above the previous $477 million to $487 million range, and adjusted earnings of $0.23 to $0.24 per share will beat initial guidance by $0.02 to $0.06 per share. Even though those results point to relatively flat sales, most investors had expected Nuance to suffer the same revenue declines that have plagued other tech companies, and the positive news sent the stock higher.

RadioShack soared 18% as investors finally responded to news late last week that hedge fund Litespeed Management had taken a stake of more than 8% in the beleaguered electronics retailer. As Fool analyst Blake Bos noted yesterday, hedge-fund manager Jamie Zimmerman has a strong reputation from successfully navigating the choppy stock market of the early 2000s, and with a specialty in working with companies in some form of financial difficulty, RadioShack shareholders rightfully took some comfort in Zimmerman's assessment that the stock was worth her attention.

Green Dot gained 7% after analysts at Piper Jaffray said that the prepaid-card provider has seen strong performance both at Wal-Mart (WMT 0.46%) and in other retail locations. That news came as a surprise to some investors, who had expected that Wal-Mart's partnership with American Express (AXP 6.22%) on its Bluebird prepaid card offering might well threaten Green Dot's standing at the high-profile retailer. The note came after other analysts had suggested that Green Dot was having to offer its cards at lower price points in order to sustain interest.