Ebay (EBAY) edged past analyst expectations on revenue and earnings when it reported first-quarter results after Wednesday’s market close,, but disappointing guidance for the second-quarter sent the stock down almost 3% on Thursday.

The company, which is in the midst of revamping its business model as it jockeys with Amazon for a bigger slice of the online commerce pie, forecast $0.43 to $0.45 a share in profit for the current quarter, which fell short of the $0.47 a share that analysts had been looking for. Wall Street was also looking for revenue of $2.32 billion, but eBay predicted $2.28 billion to $2.32 billion.

To compete with Amazon, eBay has ramped up its advertising and marketing budgets as it tries to lure in new buyers. The company has also changed the layout of its homepage and started to de-emphasize auctions in favor of fixed-price sales, which bring more stability to revenue.

Its efforts have born some fruit. EBay added 2 million active buyers in the first quarter, bringing its total to 169 million, which is 4% more than a year ago. But that shift in strategy has been expensive. For the quarter, eBay spent 4.5% more on sales and marketing costs than a year ago, bringing its expenditure to $562 million, as its product development costs jumped 16.3% over last year to $278 million.

EBay’s stock price has been on a wild ride over the last couple of years as earnings have risen and fallen. Shares have been on the rebound after a swoon starting last October when they fell below $28. Since the beginning of December, the stock is up more than 19%.

But the biggest swing came just before that. After dipping below $23 in late June, shares shot up more than 43% in July on the glow of a solid earnings report. Rise or fall, that volatility is a good indication of just why eBay wants to move toward a business model whose revenue stream is a lot less unpredictable.