NEW YORK (TheStreet) -- Nike (NKE) shares are now at an all-time high after the stock closed at $89.50 on Friday. Shares are up 13.8% for the year to date, almost doubling the 7.3% gain in the S&P 500 (SPY) .

Why? Nike delivered an earnings slam dunk. On the heels of the company's strong fiscal first-quarter results, in which revenue was up across all categories, investors on the sidelines have a decision to make. These shares, which are already trading at a premium price-to-earnings ratio of 29 vs. the industry average P/E of 18, won't get cheap any time soon. But it's still not too late to add to a long-term position.

And here's why Nike remains a strong buy.

NKE Chart

NKE data by YCharts

Aside from being a consistently safe investment, Nike pays a decent yield of 1.1%. And at $89.50, Nike shares have only reached their median analyst target, according Yahoo! Finance. Nike shares have a high price target of $100 among the 23 analysts that cover the company, which suggests a premium of close to 15%.

Following the company's 14.5% year-over-year jump in revenue, which beat estimates by $150 million, analysts will have to revise upward. Despite stiff competition from Adidas (ADDYY) and Under Armour (UA) , Nike is showing no meaningful signs of slowing down.

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