U.S. small business owners gained confidence in April and were surprisingly bullish about capital expenditure plans, further supporting views that economic growth was rebounding after a dismal first quarter. The National Federation of Independent Business said on Tuesday its Small Business Optimism Index rose 1.7 points to 96.9 last month. The data add to the evidence that the weakening in growth in first quarter was largely due to ‘transitory’ factors,” said Jim O’Sullivan, chief U.S. economist at High Frequency Economics in Valhalla, New York.