While the Dow Jones Industrial Average (^DJI 0.56%) was tumbling in early trading Tuesday, shedding more than 40 points as of 11:30 a.m. EST, three stocks were notching notable gains. Dow component Cisco Systems (CSCO 0.52%) was up more than than 1%, while hard-drive maker Seagate (STX) added nearly 3%. iRobot (IRBT 6.53%), which had enjoyed a solid gain yesterday, surged 20% higher on Tuesday.

Inflation stays muted
Data released early on Tuesday showed that inflation in the U.S. economy was largely subdued. Core consumer price index on a month-to-month basis rose more than expected, but only slightly -- increasing 0.20% where economists had anticipated a gain of 0.1%. However, on a year-over-year basis, core CPI came in line with expectations at 1.7%, while noncore measures of inflation (which include food and fuel) were reported lower than expected.

With inflation limited, the Federal Reserve may be more likely to continue stimulating the economy, which should be positive for the markets. Yet that didn't appear to be the case on Tuesday; investors may have been looking ahead to tomorrow, when the Fed will reveal its decision on interest rates.

Cisco announces new product
Cisco announced a new product this morning -- a Cisco Desktop as a Service solution. Using the cloud-based product, Cisco's customers can get access to a virtual desktop on a subscription basis. 

That announcement may not have been important to enough to move Cisco shares, though new products could help. Investors may have been reacting more to an upgrade from Standard & Poor's. Analysts boosted Cisco credit rating to AA- from A+. That type of upgrade generally doesn't carry as much weight as a buy recommendation from a major bank, but it does suggest that S&P believes Cisco's financial situation is improving.

Seagate gets upgraded
Seagate did benefit from a recommendation from a major bank -- analysts at JPMorgan Chase upgraded the data storage specialist from underweight to neutral. JPMorgan doesn't believe investors should run out and buy Seagate shares, but the bank no longer sees doom and gloom for the company. In fact, JPMorgan has turned much more positive on the hard-drive market in general, upgrading Seagate's main competitor, Western Digital, to buy.

Previously, JPMorgan had believed flash-based memory would largely overtake traditional hard drives in PCs, but that transition does not seem to be going as quickly as the bank anticipated.

iRobot surges on buy recommendation
We're only two days in, but so far this has been a great week for iRobot shareholders. Yesterday, shares benefited from Google's purchase of Boston Dynamics, a robotics company. Today, they're surging in the wake of Raymond James' strong buy recommendation and $39 price target.

iRobot is largely known for its household robots, most notably its Roomba autonomous vacuum. Raymond James believes the newest model will meaningfully boost sales in 2014, while iRobot's mopping robot will enter new markets.