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.

Monday was a big day for several major market averages, as the S&P jumped to nearly set a new all-time record, while the Nasdaq Composite reached its highest level since 2000. Although the overall market lacked any definitive catalyst sending shares higher, big gains for Humana (HUM 0.13%), Kandi Technologies (KNDI -1.12%), and GT Advanced Technologies (NASDAQ: GTAT) helped paint a bullish picture for market participants.

Humana rose almost 11% after the health-insurance company said that, based on proposals from the Department of Health and Human Services covering how much money Humana and its peers are eligible to receive for services related to Medicare Advantage plans, it believes that its revenue from the government program will fall less dramatically than it had originally feared. The news sent health insurers up nearly across the board, but Humana has particularly high exposure to the Medicare Advantage niche, so had the most to gain from the good news.

Kandi Technologies jumped 16% as the Chinese manufacturer and rental agency for electric vehicles said that it expects to expand its current service into key cities in the emerging-market nation, including Shanghai and Beijing. By using a Zipcar-like business model of offering its vehicles for short-term rentals, Kandi users avoid some of the inconveniences of electric-car ownership, especially the hassle of charging. Analysts believe that Kandi might be a key component of the nation's efforts to cut pollution by reducing reliance on fossil-fuel vehicles by the end of the decade.

GT Advanced Technologies soared almost 17% after releasing strong guidance along with its fourth-quarter earnings results. Ugly past results were misleading because of a new supply agreement in November with smartphone giant Apple (AAPL 1.12%), which ordered huge amounts of GT's sapphire materials for potentially greater use in future models. Revenue is expected to multiply by several times as a result of the deal, and even though margins on the Apple contract will be lower than its existing business, making it up on volume seems like a reasonable solution for GT investors.