The stock market gave a little ground back after an impressive bull run in recent days. But the Nasdaq Composite (NASDAQINDEX:^IXIC) was able to overcome the downward pressure better than other major market benchmarks. By 1 p.m. EST, the Nasdaq was actually up on the day, having stayed relatively close to the unchanged mark for much of the late-morning hours.

Helping to keep the Nasdaq supported was Tesla (NASDAQ:TSLA), which soared after getting some long-awaited news. Perhaps more surprising was that investors in Costco Wholesale (NASDAQ:COST) weren't more disappointed, as the stock managed to gain ground despite getting a vote of no confidence from no less than legendary investor Warren Buffett.

Tesla gets the S&P call

Shares of Tesla were up 9% Tuesday afternoon. Investors were pleased that the electric-auto maker finally got word that it would be included in the S&P 500 index as of Dec. 21.

Blue Tesla Model S on a road, with sun setting behind

Image source: Tesla.

Tesla had apparently qualified for inclusion in the index months ago, but index manager S&P Dow Jones Indices had held off on adding the company to the benchmark. Even with today's move, S&P Dow Jones made some special provisions for Tesla, leaving open the possibility that the massive company could get added to the index on a gradual basis rather than all at once.

Tesla is large enough that index fund managers will have to work hard to get the shares they need without creating a huge market disruption. In the past, added stocks often enjoy a move higher prior to formally becoming part of the S&P 500 -- many of which had far lower valuations than Tesla.

With the invitation finally coming, Tesla investors can get rid of this particular chip on their shoulders and instead refocus on company fundamentals. The electric vehicle pioneer has plenty of potential in areas like power storage, artificial intelligence, and engineering, but a hefty valuation arguably already takes Tesla's loyal customer base and other advantages into account.

Costco is special, even without Buffett

Elsewhere, Costco Wholesale shares rose almost 2%. The company is treating shareholders right, even if Buffett is no longer one of them.

Costco declared a special dividend for its shareholders late Monday, with investors to receive $10 per share on Dec. 11. The move is fourth time in eight years that Costco has made a special dividend payment. As CFO Richard Galanti explained, Costco has the financial flexibility and balance sheet strength to make these payments, which supplement a regular dividend that produces a yield of just 0.75%.

However, Costco investors got negative news when Buffett's Berkshire Hathaway (NYSE:BRK.A) (NYSE:BRK.B) sold off its entire stake in the warehouse retailer. For someone whose ideal holding period is forever, the decision took many by surprise.

Nevertheless, Costco's fundamental business has done well, and it shows few signs of slowing down as the holiday season approaches. That's largely the reason why Costco's stock continued to rise even with Buffett playing the role of Scrooge.

Keep your eyes on the prize

The Nasdaq has done exceptionally well, proving resilient even when other markets have been less stable. Investors should keep their eyes on the top Nasdaq stocks and take note of the good things happening to many of them.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.