Two of the day's top performing companies within the Healthcare sector are Centene Corp (NYSE: CNC) and Biogen Inc (NASD: BIIB) with a gain of 6.5% and 6.3%, respectively.

On the other hand, along with healthcare ETFs, one ETF subsequent to the sector is the Health Care Select Sector SPDR ETF (AMEX: XLV), showing a gain of 2.5% on the day, and down 4.33% year-to-date. Meanwhile, Centene Corp is down 0.27% year-to-date, while Biogen Inc, is down 3.88% year-to-date. When combined, the two (CNC and BIIB) would make up to an approximate of 2.9% of the principal capital of XLV.

Accordingly, following Healthcare as the top performing sector as of midday Monday is the Technology and Communications Sector showing a gain of 2.2%. The top two most notable companies with large Technology and Communications stocks are NetApp, Inc. (NASD: NTAP) and NVIDIA Corp (NASD: NVDA) with an increase of 5.2% and 5.1%, respectively.

The Technology Select Sector SPDR ETF (XLK), on the other hand, is one ETF closely tracking Technology & Communications stocks showing a gain of 2.1% in midday trading, and up 11.52% on a year-to-date basis. Meanwhile, NetApp, Inc. is up 23.56% year-to-date, while NVIDIA Corp is up 116.52% year-to-date. NTAP and NVDA would make up approximately 1.1% of the primary shares of XLK when combined.

Conversely, the sectors that underperformed and fared worst as of midday Monday are the Utilities sector and the Materials sector.

Among the companies in the Utilities sector are the Consolidated Edison Inc (NYSE: ED) and Dominion Resources Inc (NYSE: D) with two large stocks that had only shown a gain of 0.3% and 0.3%, respectively. In the utilities ETFs, Utilities Select Sector SPDR ETF (AMEX: XLU) is another ETF following the sector, that is up 1.0% on the day, and up 14.71% year-to-date. Meanwhile, Consolidated Edison Inc is up 18.25% year-to-date, while Dominion Resources Inc is up 12.55% year-to-date.

The most notable companies that have large Materials stocks are the Newmont Mining Corp (NYSE: NEM) and WestRock Co (NYSE: WRK) with a recorded loss of 4.1% and 2.5%, respectively. Among Material sector's ETFs, is the Materials Select Sector SPDR ETF (XLB), which increased 1.3% in midday trading, and up 9.75% on a year-to-date basis. While Newmont Mining Corp is up 101.97% year-to-date, and WestRock Co is up 1.58% year-to-date.