Catch up on today's top five analyst upgrades with this list compiled by The Fly: 1. Spirit Airlines (SAVE) upgraded to Overweight from Neutral at JPMorgan with analyst Jamie Baker saying he admits to being "clearly misgauged" over the elasticity of Spirit's passenger base following the company's Q4 TRASM outlook "surprise." 2. Ooma (OOMA) upgraded to Outperform from Market Perform at William Blair with analyst Bhavan Suri saying the "solid" quarter shows Ooma's "consistent execution." 3. DaVita (DVA) upgraded to Outperform from Market Perform at Raymond James with analyst John Ransom saying the stock has fallen about 18% since the company reported a Q3 earnings miss and since the defeat of the California ballot initiative, creating an attractive entry point. 4. Aspen Technology (AZPN) upgraded to Buy from Hold at Canaccord with analyst David Hynes citing valuation. 5. Union Pacific (UNP) upgraded to Buy from Hold at Deutsche Bank with analyst Amit Mehrotra saying after several years of "weak" cost control, Union Pacific is now positioned for at least $3B in profit improvement. This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.

Deutsche Bank placed a "Catalyst Call: Buy" on shares of Union Pacific (UNP) as a short-term investment idea. With all the attention Norfolk Southern (NSC) is getting in recent months, it is easy to overlook developments at other railroads, the analyst tells investors in a research note. The firm says Union Pacific is now the worst performing pail stock year-to-date. However, operating metrics "clearly show that UNP's renewed efforts on operations are gaining traction," contends Deutsche Bank. It keeps a Buy rating on the shares with a $266 price target.