BIIB option chain

Strikes around the forward, as they were quoted at the close

Data as of 6 November 2026 (end of day)

2026-11-20(14 days)ATM 36.76%±17.98skew +0.56

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	9	$38.20	$41.00	—	$210.00	—	—	—	—	—
19	16	$28.60	$31.70	—	$220.00	—	—	—	—	—
0	2	$26.20	$29.00	—	$222.50	—	—	—	—	—
0	1	$23.60	$26.80	—	$225.00	—	—	—	—	—
0	1	$21.60	$24.60	—	$227.50	—	—	—	—	—
0	485	$19.30	$22.90	—	$230.00	—	—	—	—	—
0	1	$17.30	$20.10	—	$232.50	—	—	—	—	—
0	12	$15.10	$17.80	—	$235.00	39.02%	$1.90	$2.55	621	1
0	34	$13.30	$16.40	—	$237.50	—	—	—	—	—
0	411	$11.40	$14.50	—	$240.00	38.06%	$3.00	$3.80	1,261	2
0	3	$10.00	$12.70	—	$242.50	—	—	—	—	—
1	23	$9.20	$10.60	—	$245.00	—	—	—	—	—
0	4	$6.60	$9.30	—	$247.50	37.59%	$5.00	$7.40	159	1
1	165	$6.40	$7.70	36.68%	$250.00	—	$6.50	$8.00	61	0
3	45	$5.40	$6.80	37.62%	$252.50	—	$7.50	$10.40	12	0
1	321	$3.90	$5.40	35.25%	$255.00	—	$9.30	$12.30	362	0
1	94	$3.50	$4.70	36.95%	$257.50	—	$10.90	$13.40	14	0
3	369	$2.65	$3.80	36.22%	$260.00	—	$12.70	$15.40	156	0
27	18	$1.90	$2.60	37.50%	$265.00	—	—	—	—	—
—	—	—	—	—	$270.00	—	$20.80	$23.50	1	0
—	—	—	—	—	$280.00	—	$29.50	$32.70	6	0

Forward $249.80. The 25-delta put carries +0.56 volatility points over the 25-delta call.

2026-12-18(42 days)ATM 51.34%±43.59skew +1.37

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	70	$59.40	$63.00	—	$190.00	—	—	—	—	—
0	147	$55.20	$58.40	—	$195.00	—	—	—	—	—
2	724	$51.10	$54.40	—	$200.00	—	—	—	—	—
0	136	$46.40	$49.70	—	$205.00	—	—	—	—	—
6	576	$42.80	$45.10	—	$210.00	—	—	—	—	—
0	185	$38.10	$41.00	—	$215.00	52.81%	$4.10	$5.00	23	100
6	443	$35.10	$37.40	—	$220.00	50.68%	$4.30	$6.20	235	12
0	74	$30.80	$33.80	—	$225.00	51.94%	$6.60	$7.30	344	6
0	326	$28.00	$30.40	—	$230.00	51.18%	$8.10	$8.60	1,341	4
10	219	$24.70	$26.10	—	$235.00	51.74%	$9.90	$10.80	1,072	54
0	1,158	$21.30	$23.50	—	$240.00	52.30%	$10.90	$14.30	520	0
0	1,104	$18.50	$21.60	—	$245.00	52.42%	$13.40	$16.50	57	1
7	391	$16.10	$19.10	—	$250.00	51.85%	$15.60	$19.00	2,049	0
33	1,808	$14.20	$16.20	51.31%	$255.00	—	$18.80	$20.90	177	0
5	519	$12.30	$14.60	52.05%	$260.00	—	$21.60	$24.50	18	0
22	1,153	$10.40	$12.60	51.57%	$265.00	—	$24.50	$27.50	8	0
0	102	$9.00	$10.00	50.29%	$270.00	—	$27.20	$30.90	11	0
2	75	$6.80	$9.20	49.94%	$275.00	—	—	—	—	—
8	86	$5.60	$8.30	50.51%	$280.00	—	—	—	—	—
1	54	$4.60	$7.20	50.57%	$285.00	—	—	—	—	—
157	97	$2.70	$3.50	48.66%	$300.00	—	$51.50	$54.40	3	0

Forward $250.30. The 25-delta put carries +1.37 volatility points over the 25-delta call.

2027-03-19(133 days)ATM 44.06%±67.16skew +2.71

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	3	$91.50	$95.20	—	$160.00	—	—	—	—	—
0	6	$86.90	$91.00	—	$165.00	—	—	—	—	—
0	36	$82.40	$86.50	—	$170.00	—	—	—	—	—
0	10	$78.00	$81.50	—	$175.00	—	—	—	—	—
0	5	$73.70	$77.80	—	$180.00	—	—	—	—	—
0	4	$69.60	$73.10	—	$185.00	—	—	—	—	—
0	12	$65.80	$69.00	—	$190.00	—	—	—	—	—
0	14	$61.60	$65.50	—	$195.00	—	—	—	—	—
0	37	$57.80	$61.10	—	$200.00	—	—	—	—	—
0	63	$50.40	$53.50	—	$210.00	45.99%	$7.70	$11.30	35	0
1	657	$43.40	$46.90	—	$220.00	45.48%	$10.60	$14.40	228	1
0	60	$37.10	$40.50	—	$230.00	45.06%	$14.30	$17.90	70	0
0	41	$31.30	$35.00	—	$240.00	44.49%	$18.30	$22.10	34	0
0	152	$26.10	$29.00	—	$250.00	44.23%	$23.10	$27.00	22	0
0	83	$21.50	$24.90	44.08%	$260.00	—	$28.50	$32.40	127	0
0	26	$17.50	$21.30	43.93%	$270.00	—	$34.40	$38.20	8	0
0	42	$14.00	$17.70	43.33%	$280.00	—	$41.50	$44.10	1	0
0	261	$11.00	$14.80	42.93%	$290.00	—	—	—	—	—
0	108	$9.40	$10.90	42.05%	$300.00	—	—	—	—	—
0	29	$7.00	$10.20	42.77%	$310.00	—	—	—	—	—
0	72	$5.60	$7.40	41.62%	$320.00	—	—	—	—	—

Forward $252.54. The 25-delta put carries +2.71 volatility points over the 25-delta call.

2027-04-16(161 days)ATM 43.28%±72.91skew +3.44

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	1	$125.00	$129.20	—	$125.00	—	—	—	—	—
0	5	$120.40	$124.40	—	$130.00	—	—	—	—	—
0	6	$59.50	$63.00	—	$200.00	45.34%	$6.20	$10.00	4	0
0	12	$52.60	$55.50	—	$210.00	—	—	—	—	—
1	80	$45.90	$49.00	—	$220.00	44.56%	$12.10	$15.70	1	0
0	1	$40.30	$42.50	—	$230.00	44.54%	$15.90	$19.70	4	0
0	10	$34.10	$36.70	—	$240.00	43.70%	$20.00	$23.50	5	0
0	7	$29.20	$31.80	—	$250.00	—	—	—	—	—
0	5	$24.30	$27.60	43.48%	$260.00	—	$30.30	$34.00	11	0
0	11	$20.00	$23.60	42.90%	$270.00	—	—	—	—	—
0	8	$16.50	$19.70	42.27%	$280.00	—	—	—	—	—
0	14	$13.50	$17.00	42.26%	$290.00	—	—	—	—	—
0	8	$10.50	$14.30	41.57%	$300.00	—	—	—	—	—
0	5	$8.50	$12.40	41.78%	$310.00	—	—	—	—	—
0	13	$6.60	$10.10	41.12%	$320.00	—	—	—	—	—
—	—	—	—	—	$380.00	—	$129.00	$132.30	—	0

Forward $253.68. The 25-delta put carries +3.44 volatility points over the 25-delta call.

2027-06-17(223 days)ATM 42.22%±84.18skew +3.83

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	3	$95.40	$99.10	—	$160.00	—	—	—	—	—
0	1	$91.10	$94.50	—	$165.00	—	—	—	—	—
0	5	$87.30	$90.60	—	$170.00	—	—	—	—	—
0	5	$82.70	$86.20	—	$175.00	—	—	—	—	—
0	6	$78.70	$82.40	—	$180.00	—	—	—	—	—
0	2	$74.80	$78.40	—	$185.00	—	—	—	—	—
0	4	$71.00	$74.60	—	$190.00	44.54%	$6.30	$10.10	16	0
0	8	$67.30	$71.20	—	$195.00	44.68%	$7.40	$11.70	63	0
0	21	$63.90	$67.60	—	$200.00	44.20%	$8.80	$12.60	2	0
0	5	$56.90	$60.00	—	$210.00	44.12%	$12.00	$15.60	20	0
1	236	$50.40	$53.30	—	$220.00	44.37%	$16.10	$19.10	262	0
0	25	$44.40	$47.20	—	$230.00	43.15%	$18.90	$22.90	16	0
0	69	$38.70	$42.10	—	$240.00	—	—	—	—	—
0	13	$34.10	$37.30	—	$250.00	42.36%	$28.00	$31.90	90	0
0	241	$29.00	$32.20	42.28%	$260.00	—	$33.50	$37.30	250	0
0	16	$25.00	$28.50	42.22%	$270.00	—	—	—	—	—
0	372	$21.00	$24.80	41.61%	$280.00	—	—	—	—	—
0	91	$18.00	$20.90	41.01%	$290.00	—	$52.50	$56.00	3	0
1	178	$15.10	$18.30	40.84%	$300.00	—	—	—	—	—
0	1	$12.50	$16.00	40.63%	$310.00	—	—	—	—	—
0	1	$7.00	$10.60	40.28%	$340.00	—	—	—	—	—

Forward $255.08. The 25-delta put carries +3.83 volatility points over the 25-delta call.

2027-09-17(315 days)ATM 40.72%±97.57skew +3.21

Calls					Strike	Puts
Volume	Open int	Bid	Ask	IV		IV	Bid	Ask	Open int	Volume
0	5	$116.00	$119.80	—	$140.00	—	—	—	—	—
0	1	$83.00	$87.00	—	$180.00	—	—	—	—	—
—	—	—	—	—	$185.00	42.65%	$7.20	$11.30	5	0
—	—	—	—	—	$190.00	42.63%	$8.50	$12.60	7	0
0	3	$72.00	$75.50	—	$195.00	42.68%	$9.80	$14.20	5	0
3	8	$68.70	$72.00	—	$200.00	42.55%	$11.30	$15.60	18	0
0	5	$62.00	$65.50	—	$210.00	42.44%	$14.50	$19.00	4	0
0	27	$55.50	$59.90	—	$220.00	42.03%	$18.00	$22.50	3	0
0	104	$50.00	$54.00	—	$230.00	—	—	—	—	—
0	7	$44.50	$48.50	—	$240.00	41.59%	$26.50	$31.00	44	0
0	16	$39.50	$43.50	—	$250.00	41.53%	$31.50	$36.00	230	0
0	2	$35.00	$39.00	41.32%	$260.00	—	$37.00	$41.00	3	0
0	32	$31.00	$35.00	41.13%	$270.00	—	—	—	—	—
0	200	$27.00	$31.00	40.55%	$280.00	—	—	—	—	—
0	34	$23.50	$27.50	40.15%	$290.00	—	—	—	—	—
0	19	$20.50	$24.50	39.95%	$300.00	—	—	—	—	—
0	51	$17.50	$22.00	39.70%	$310.00	—	—	—	—	—
0	59	$15.50	$19.50	39.70%	$320.00	—	—	—	—	—
0	2	$13.00	$17.50	39.41%	$330.00	—	—	—	—	—
0	202	$11.50	$15.40	39.39%	$340.00	—	—	—	—	—
0	10	$9.50	$14.00	39.23%	$350.00	—	—	—	—	—

Forward $257.93. The 25-delta put carries +3.21 volatility points over the 25-delta call.

How to read this

Calls on the left, puts on the right, the strike between them — the layout every chain uses. Each block is one expiration, and the heading carries its days to expiry, the at-the-money implied volatility, and the one-standard-deviation move that volatility implies over that time.

Only the 21 strikes nearest the forward are stored, which is the part of the board that carries the volume. The shaded side is in the money: below the forward for calls, above it for puts.

Implied volatility is shown on the out-of-the-money side only. An in-the-money option is nearly all intrinsic value quoted on a wide market, so a volatility solved from it would look authoritative and mean very little. The price is still shown, because the price is real; the blank is deliberate.