Merck (MRK) provided guidance for the first quarter of 2012, and while its outlook came in below consensus expectations, the main driver behind the weakness was currency, a non-operating event. Specifically, the drug maker expects foreign exchange to impact sales 1% to 2% in its first quarter, with non-GAAP earnings per share expected to come in between $0.95 and $0.98 per share for the period (consensus was at $1.01). Despite the negative currency impact, Merck re-confirmed its guidance for full-year 2012 non-GAAP earnings per share to be between $3.75 and $3.85 per share. Though the news today suggests that some analysts were too optimistic about Merck’s bottom-line numbers, we think the company’s long-term trajectory remains in line with our forecasts. Our fair value estimate for the drug maker remains unchanged.