Statistics of Price Movements of Biogen Inc (BIIB)

The price movements of Biogen Inc (ticker BIIB) are summarized in five ways:

• Table 1. Statistics of daily price changes using the closing prices
• Table 2. Statistics of daily price changes using the closing and opening prices
• Table 3 – 7. Statistics of daily price changes when BIIB opened with an increase of 1%, 2%, 3%, 4%, or more than 5%
• Table 8 – 10. Statistics of stock price changes in the 20 days after BIIB had a big price move
• Table 11. Statistics of daily price changes in the 20 days after BIIB moved 5% with twice the 30-day average volume

The statistics are calculated using BIIB's price data across 1,547 trading days from 2015 to 2020.

Table 1. Statistics of BIIB one-day price changes

In this table, the one-day price change is calculated using the closing price and the previous day's closing price.

In the past 1,547 trading days, 49.2% of the time (760 days), BIIB closed above the previous day's closing price. 47.2% of the time (729 days), it closed below the previous day's closing price. 3.7% of the time (57 days), it did not change.

Also see: VIX price movement study.

BIIB Price Change (%)	Number of Days	% of Total Sessions
26 – 27%	1	0.06%
19 – 20%	1	0.06%
17 – 18%	1	0.06%
13 – 14%	1	0.06%
10 – 11%	2	0.13%
9 – 10%	2	0.13%
8 – 9%	2	0.13%
7 – 8%	2	0.13%
6 – 7%	3	0.19%
5 – 6%	10	0.65%
4 – 5%	20	1.29%
3 – 4%	35	2.26%
2 – 3%	84	5.43%
1 – 2%	223	14.42%
0 – 1%	373	24.13%
0%	57	3.69%
0 – -1%	352	22.77%
-1 – -2%	187	12.10%
-2 – -3%	110	7.12%
-3 – -4%	42	2.72%
-4 – -5%	18	1.16%
-5 – -6%	7	0.45%
-6 – -7%	3	0.19%
-7 – -8%	4	0.26%
-8 – -9%	1	0.06%
-9 – -10%	1	0.06%
-10 – -11%	1	0.06%
-12 – -13%	1	0.06%
-22 – -23%	1	0.06%
-29 – -30%	1	0.06%

Table 2. Statistics of BIIB: Closing vs. Open

In this table, instead of using the closing price of the previous day, the opening price is used to calculate the one-day price change of BIIB.

46.5% of the time (720 days), BIIB closed above the opening price. 49.8% of the time (771 days), it closed below the opening price. 3.6% of the time (56 days), it closed where it started.

Closing - Open (%)	Number of Days	% of Total Sessions
16 – 17%	1	0.06%
9 – 10%	1	0.06%
8 – 9%	1	0.06%
7 – 8%	2	0.13%
6 – 7%	1	0.06%
5 – 6%	3	0.19%
4 – 5%	15	0.97%
3 – 4%	22	1.42%
2 – 3%	89	5.75%
1 – 2%	191	12.35%
0 – 1%	394	25.47%
0%	56	3.62%
0 – -1%	396	25.60%
-1 – -2%	233	15.06%
-2 – -3%	90	5.82%
-3 – -4%	32	2.07%
-4 – -5%	12	0.78%
-5 – -6%	4	0.26%
-6 – -7%	2	0.13%
-8 – -9%	1	0.06%
-9 – -10%	1	0.06%

Table 3. One-day performance when BIIB opened 5% higher than previous close

In the past 1,547 trading days, BIIB opened more than 5% higher than the previous day's closing price 13 times. Of these days, 38.5% (5 days) had closing prices above the opening price, and 61.5% (8 days) had closing prices below the opening price.

Closing - Open (%)	Number of Days	% of Total Sessions
4 – 5%	1	7.69%
3 – 4%	1	7.69%
2 – 3%	1	7.69%
0 – 1%	2	15.38%
0 – -1%	1	7.69%
-1 – -2%	2	15.38%
-3 – -4%	2	15.38%
-4 – -5%	1	7.69%
-5 – -6%	1	7.69%
-9 – -10%	1	7.69%

Table 4. Closing vs. open when BIIB opened 4–5% higher

On 2 days, BIIB opened 4–5% higher than the previous day's closing price. Of these days, 50.0% (1 days) had closing prices above the opening price, and 50.0% (1 days) had closing prices below the opening price.

Closing - Open (%)	Number of Days	% of Total Sessions
1 – 2%	1	50.00%
-1 – -2%	1	50.00%

Table 5. Closing vs. open when BIIB open 3 – 4% higher

8 times BIIB opened 3 – 4% higher than the previous day's closing price. Among these days, 62.5% (5 days) closed above the opening price, 37.5% (3 days) closed below the opening price.

Closing - Open (%)	Number of Days	% of Total Sessions
9 – 10%	1	12.50%
1 – 2%	1	12.50%
0 – 1%	3	37.50%
0 – -1%	1	12.50%
-1 – -2%	2	25.00%

Table 6. Closing vs. open when BIIB open 2 – 3% higher

11 times BIIB opened 2 – 3% higher than the previous day's closing price. Among these days, 63.6% (7 days) closed above the opening price, 36.4% (4 days) closed below the opening price.

Closing - Open (%)	Number of Days	% of Total Sessions
2 – 3%	3	27.27%
1 – 2%	1	9.09%
0 – 1%	3	27.27%
0 – -1%	1	9.09%
-1 – -2%	1	9.09%
-2 – -3%	2	18.18%

Table 7. Closing vs. open when BIIB open 1 – 2% higher

96 times BIIB opened 1 – 2% higher than the previous day's closing price. Among these days, 50.0% (48 days) closed above the opening price, 50.0% (48 days) closed below the opening price.

Closing - Open (%)	Number of Days	% of Total Sessions
7 – 8%	1	1.04%
5 – 6%	1	1.04%
4 – 5%	2	2.08%
3 – 4%	1	1.04%
2 – 3%	9	9.38%
1 – 2%	15	15.62%
0 – 1%	19	19.79%
0 – -1%	22	22.92%
-1 – -2%	13	13.54%
-2 – -3%	8	8.33%
-3 – -4%	2	2.08%
-4 – -5%	3	3.12%

Table 8. Periods when BIIB moved 15% or more

In this table, we track the price movements in the 20 days after BIIB had a one-day price change of at least 15%.

Date	Price Change	Price Change after 15% Move
Days after:		1	4	7	10	13	16	19
20191022	26.1%	-1.1	4.8	6.0	3.7	4.0	.0	.3
20180706	19.6%	-1.0	-2.7	-.7	.3	7.4	-7.3	-2.7
20200205	17.5%	1.3	-.2	.0	2.5	-2.1	-6.8	-5.1
20150724	-22%	3.1	5.7	10.1	3.0	5.6	5.3	3.3
20190321	-29.2%	-4.5	1.4	2.5	3.6	4.7	3.4	.1

Table 8a. BIIB average price changes following a 15% up day

Of the 1,547 trading days from 2015 to 2020, there were 3 days in which BIIB was up more than 15%. This table shows the average price changes over the 3 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ 15%	-.2	.6	1.8	2.2	3.1	-4.7	-2.5

Table 8b. BIIB average price changes following a 15% down day

Of the 1,547 trading days from 2015 to 2020, there were 2 days in which BIIB was down more than -15%. This table shows the average price changes over the 2 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ -15%	-.7	3.5	6.3	3.3	5.1	4.4	1.7

Table 9. Periods when BIIB moved 10% or more

In this table, we track the price movements in the 20 days after BIIB had a one-day price change of at least 10%.

Date	Price Change	Price Change after 10% Move
Days after:		1	4	7	10	13	16	19
20191022	26.1%	-1.1	4.8	6.0	3.7	4.0	.0	.3
20180706	19.6%	-1.0	-2.7	-.7	.3	7.4	-7.3	-2.7
20200205	17.5%	1.3	-.2	.0	2.5	-2.1	-6.8	-5.1
20200313	13.5%	-7.7	-5.6	-9.5	-2.8	-3.9	2.0	5.2
20150130	10.1%	.2	3.2	1.5	.6	3.1	5.0	5.4
20200807	10.1%	-1.8	-5.6	-5.5	-9.4	-8.7	-5.9	-9.7
20180726	-10.1%	-1.3	-.2	-1.0	.6	-.3	.1	.1
20160607	-12.7%	.5	-3.4	-4.2	-7.9	-9.4	-5.5	-3.1
20150724	-22%	3.1	5.7	10.1	3.0	5.6	5.3	3.3
20190321	-29.2%	-4.5	1.4	2.5	3.6	4.7	3.4	.1

Table 9a. BIIB average price changes following a 10% up day

Of the 1,547 trading days from 2015 to 2020, there were 6 days in which BIIB was up more than 10%. This table shows the average price changes over the 6 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ 10%	-1.7	-1.0	-1.4	-.8	-.0	-2.2	-1.1

Table 9b. BIIB average price changes following a 10% down day

Of the 1,547 trading days from 2015 to 2020, there were 4 days in which BIIB was down more than -10%. This table shows the average price changes over the 4 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ -10%	-.5	.9	1.8	-.2	.1	.8	.1

Table 10. Periods when BIIB moved 5% or more

In this table, we track the price movements in the 20 days after BIIB had a one-day price change of at least 5%.

Date	Price Change	Price Change after 5% Move
Days after:		1	4	7	10	13	16	19
20191022	26.1%	-1.1	4.8	6.0	3.7	4.0	.0	.3
20180706	19.6%	-1.0	-2.7	-.7	.3	7.4	-7.3	-2.7
20200205	17.5%	1.3	-.2	.0	2.5	-2.1	-6.8	-5.1
20200313	13.5%	-7.7	-5.6	-9.5	-2.8	-3.9	2.0	5.2
20150130	10.1%	.2	3.2	1.5	.6	3.1	5.0	5.4
20200807	10.1%	-1.8	-5.6	-5.5	-9.4	-8.7	-5.9	-9.7
20150320	9.7%	-2.6	-9.9	-11.3	-13.3	-10.6	-11.1	-9.9
20160802	9.3%	-2.7	-5.0	-4.7	-5.1	-4.0	-6.3	-7.3
20200317	8.3%	-2.2	-11.8	-.1	3.6	-1.6	3.8	5.8
20161109	8.2%	1.4	.9	-.9	-4.4	-5.0	-7.5	-9.0
20160721	7.6%	1.9	2.1	6.9	11.4	11.3	11.1	11.1
20200326	7%	-2.7	-3.8	2.1	5.3	9.5	12.3	-2.3
20161107	6.7%	-.0	8.0	7.5	7.7	3.5	2.4	.5
20200330	6.5%	.1	-4.9	.3	2.2	7.0	4.1	-5.8
20200302	6.3%	-3.7	-3.0	-10.3	-14.1	-12.2	-15.8	-9.5
20181226	5.9%	-.3	1.9	7.8	10.7	11.9	14.6	14.8
20150826	5.8%	2.1	-1.9	1.3	1.8	6.0	9.1	.3
20151027	5.8%	1.1	4.3	.8	2.3	-2.0	.5	1.2
20190326	5.7%	-1.3	-.2	.9	2.0	.7	-2.5	-1.8
20150107	5.5%	-.8	-.1	-.1	2.4	2.6	.0	11.5
20160406	5.2%	-2.3	-4.3	-4.0	-4.9	1.9	.5	-2.1
20200408	5.2%	1.3	5.3	8.1	-6.0	-4.3	-6.3	-3.9
20160127	5.1%	-2.7	-2.6	-3.4	-7.7	-9.5	-5.2	-5.2
20160421	5.1%	1.1	.2	-2.1	-5.4	-2.3	-6.3	-5.5
20200727	5%	-2.0	-4.0	-3.5	4.9	.8	.9	-3.2
20201109	-5.1%	.0	5.2	2.0	3.0	2.3	2.9	4.1
20180618	-5.2%	1.0	2.4	-.4	2.3	3.4	19.3	20.5
20200227	-5.3%	-.5	5.9	-4.2	-13.3	-1.5	-10.1	-8.1
20150921	-5.5%	.6	-4.2	-1.8	-3.6	-5.8	-13.8	-8.3
20150806	-5.6%	-2.4	.0	-.2	-2.1	-11.0	-4.1	-3.9
20150824	-5.8%	1.2	9.1	9.3	8.6	12.3	14.9	13.0
20181218	-5.8%	-.7	-5.5	-.1	2.1	8.0	10.8	12.1
20180214	-6.5%	1.1	-2.9	-1.1	-2.4	-3.1	-3.8	-4.3
20200309	-6.5%	2.8	2.7	.5	-9.4	2.6	6.5	1.1
20150424	-6.6%	-3.1	-6.9	-4.0	-.8	-2.9	-1.6	-.1
20190207	-7.3%	2.1	4.1	7.8	4.0	6.1	8.2	3.0
20200401	-7.3%	3.8	2.7	9.5	11.5	15.7	-.3	4.1
20200618	-7.5%	4.1	1.1	.0	1.9	3.1	7.1	8.7
20200316	-7.6%	8.4	-1.0	1.2	12.2	8.1	6.9	14.0
20200312	-8.6%	13.5	11.1	.1	13.4	17.7	11.8	17.9
20200422	-9.4%	-1.9	2.4	-1.7	2.9	10.1	6.0	4.1
20180726	-10.1%	-1.3	-.2	-1.0	.6	-.3	.1	.1
20160607	-12.7%	.5	-3.4	-4.2	-7.9	-9.4	-5.5	-3.1
20150724	-22%	3.1	5.7	10.1	3.0	5.6	5.3	3.3
20190321	-29.2%	-4.5	1.4	2.5	3.6	4.7	3.4	.1

Table 10a. BIIB average price changes following a 5% up day

Of the 1,547 trading days from 2015 to 2020, there were 25 days in which BIIB was up more than 5%. This table shows the average price changes over the 25 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ 5%	-1.0	-1.4	-.5	-.5	.1	-.6	-1.1

Table 10b. BIIB average price changes following a 5% down day

Of the 1,547 trading days from 2015 to 2020, there were 20 days in which BIIB was down more than -5%. This table shows the average price changes over the 20 days.

Average Type	Average Price Change
Days after:	1	4	7	10	13	16	19
Avg for Change ≥ -5%	1.4	1.5	1.2	1.5	3.3	3.2	3.9

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Also see: VIX price movement study.