| 102.90 Data as of May 17 |  +1.08 / +1.06%Today’s Change | 81.82 Today|||52-Week Range 119.54 | +9.77% Year-to-Date |
| Mutual fund holders | 59.36% |
| Other institutional | 39.23% |
| Individual stakeholders | 1.55% |
| 3/31/2013 | VIKING GLOBAL INVESTORS LP Bought 5.4 Million shares of Alexion Pharmaceuticals I... |
| 3/31/2013 | CAPITAL RESEARCH & MANAGEMENT CO... Bought 2.8 Million shares of Alexion Pharmaceuticals I... |
| 3/31/2013 | COLUMBIA MANAGEMENT INVESTMENT A... Bought 1.1 Million shares of Alexion Pharmaceuticals I... |
| Stockholder | Stake | Shares owned | Total value ($) | Shares bought / sold | Total change |
|---|---|---|---|---|---|
| Capital Research & Management Co.... | 10.92% | 21,304,282 | 2,087,819,636 | +2,841,682 | +15.39% |
| T. Rowe Price Associates, Inc. | 9.24% | 18,034,669 | 1,767,397,562 | -465,705 | -2.52% |
| Fidelity Management & Research Co... | 7.09% | 13,821,302 | 1,354,487,596 | -1,090,577 | -7.31% |
| Jennison Associates LLC | 5.18% | 10,104,849 | 990,275,202 | +48,163 | +0.48% |
| Viking Global Investors LP | 4.85% | 9,462,442 | 927,319,316 | +5,448,200 | +135.72% |
| BlackRock Fund Advisors | 4.84% | 9,445,149 | 925,624,602 | +355,946 | +3.92% |
| The Vanguard Group, Inc. | 4.53% | 8,827,198 | 865,065,404 | +308,137 | +3.62% |
| Sands Capital Management LLC | 4.32% | 8,420,336 | 825,192,928 | +341,730 | +4.23% |
| SSgA Funds Management, Inc. | 4.00% | 7,794,640 | 763,874,720 | +79,624 | +1.03% |
| Wells Capital Management, Inc. | 3.25% | 6,340,143 | 621,334,014 | -13,309 | -0.21% |
| Mutual fund | Stake | Shares owned | Total value ($) | Shares bought / sold | Total change |
|---|---|---|---|---|---|
| American Funds Growth Fund of Ame... | 4.74% | 9,250,000 | 906,500,000 | 0 | 0.00% |
| Fidelity Growth Company Fund | 3.11% | 6,074,060 | 595,257,880 | -350,000 | -5.45% |
| Wells Fargo Advantage Growth Fund | 1.78% | 3,480,000 | 341,040,000 | +123,000 | +3.66% |
| T Rowe Price Health Sciences Fund | 1.68% | 3,284,500 | 321,881,000 | -500 | -0.02% |
| Harbor Capital Appreciation Fund | 1.40% | 2,727,167 | 267,262,366 | +57,311 | +2.15% |
| Vanguard Total Stock Market Index... | 1.32% | 2,582,572 | 253,092,056 | +126,499 | +5.15% |
| American Funds Investment Company... | 1.21% | 2,350,000 | 230,300,000 | 0 | 0.00% |
| American Variable Insurance Serie... | 1.20% | 2,340,000 | 229,320,000 | 0 | 0.00% |
| Columbia Select Large Cap Growth ... | 1.17% | 2,285,168 | 223,946,464 | -77,161 | -3.27% |
| American Funds AMCAP Fund | 1.14% | 2,225,000 | 218,050,000 | 0 | 0.00% |
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