Monday began the week on Wall Street on a positive note, as major benchmarks enjoyed another day of small gains that marked an all-time high for the S&P 500. Historically, now's the time that many start looking for a seasonal Santa Claus rally heading into the end of the year, but a lot this year will depend on what progress Congress makes in passing a tax reform package. Even news of an explosion near the Port Authority in New York City wasn't enough to dampen enthusiasm among investors. Good news from several corners of the economy also helped the overall market, and Southwestern Energy (SWN), CenturyLink (LUMN -0.75%), and (BYON 1.32%) were among the best performers on the day. Below, we'll look more closely at these stocks to tell you why they did so well.

Southwestern Energy gasses up

Shares of Southwestern Energy gained almost 6% on a solid day for the energy sector. Oil prices climbed 1% to come close to the $58-per-barrel level, and natural gas prices were up by an even greater amount on a percentage basis. Southwestern Energy has a concentration in natural-gas-producing assets, and its low production costs have been able to keep the company profitable even at times when many of its competitors are still struggling to break even. Many industry watchers are hopeful that as natural gas export terminals start coming online, it will help pull prices upward, aiding Southwestern Energy and its peers. Yet Southwestern will have to endure plenty of uncertainty before it can hope to regain its huge losses since its peak in 2014.

Drilling rig in the background in a green field with a low-hanging tree in the foreground.

Image source: Southwestern Energy.

Is CenturyLink a bargain? Top execs think so

CenturyLink stock gained 8% following bullish news that key insiders had made share purchases. According to SEC filings dated Friday, CEO Glenn Post spent more than $700,000 buying 50,000 shares of CenturyLink, while COO Jeff Storey added more than 70,000 shares at a cost of more than $1 million. Several other directors of the company followed suit with smaller purchases. CenturyLink has fallen lately because of concerns about its recently completed merger with Level 3 Communications, but executives remain confident about the company's future, and they've been willing to put their money where their mouths are. gains from bitcoin fever

Finally, shares of jumped 22%. The investment management arm of Morgan Stanley revealed an 11% stake in the e-commerce retailer, which has become increasingly known for its connection to bitcoin and other cryptocurrencies. Given the difficulties that the retail operations of the company have had, the logical conclusion to draw is that the Wall Street investment bank is interested in because of its bitcoin exposure, both in the short run because of its holdings of the cryptocurrency and in the long run because of its willingness to embrace the trend. Still, if another pullback in bitcoin occurs, it could make Overstock shares cool off in a hurry.