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Ultragenyx Pharmaceutical Inc. short interest

20.1M shares of Ultragenyx Pharmaceutical were sold short at the 15 October 2026 settlement, near the top of its range over the last year (7.1M to 20.3M). Short sellers would need 5.2 days of normal trading to buy them back.

Shares sold short20.1Mat 15 Oct 2026
Change on the settlement before-1.0%+132% over a year
Days to cover5.18at 3.9M shares a day
Of shares in issue20.43%shares short over shares outstanding
New to this? How to read this page
  1. Short interest is the number of shares investors have borrowed and sold, betting the price will fall, and not yet bought back.
  2. Days to cover is shares short over an average day's trading: how many days it would take short sellers to buy them all back. Above 5 or so is high.
  3. Rising short interest says more investors are betting against the stock. A crowded short can also rise fast if shorts rush to buy back.
  4. Brokers report it twice a month to FINRA, about ten days after each settlement date.
  5. What is short interest?

Short interest, days to cover and the price

Short interest is near the top of its range over the last year (7.1M to 20.3M), and the share price moved -50% over the last year.

Shares sold shortDays to coverShare price

Three charts on one timeline. Top: shares sold short at each settlement. Middle: days to cover, taller meaning shorts would need longer to buy back. Bottom: the share price, so you can see whether shorts added as the price fell or rose.

How it compares

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    Every settlement since 29 Dec 2017 as a table
    SettlementShares shortChangeAverage daily volumeDays to cover
    15 October 202620.1M-1.0%3.9M5.18
    30 September 202620.3M+22.8%6.5M3.13
    15 September 202616.6M-3.3%7.5M2.22
    31 August 202617.1M+7.9%2.1M8.00
    14 August 202615.9M+6.2%2.0M7.78
    31 July 202615.0M+11.4%1.8M8.28
    15 July 202613.4M-17.2%1.9M6.94
    30 June 202616.2M+13.3%4.5M3.60
    15 June 202614.3M-2.7%1.6M8.85
    29 May 202614.7M+5.2%1.5M9.83
    15 May 202614.0M+2.3%1.7M8.22
    30 April 202613.7M+13.0%1.6M8.40
    15 April 202612.1M+5.9%1.7M7.09
    31 March 202611.4M+14.9%2.4M4.81
    13 March 20269.9M+3.5%2.1M4.78
    27 February 20269.6M-2.7%1.8M5.40
    13 February 20269.9M+8.4%2.5M3.92
    30 January 20269.1M+2.6%2.4M3.85
    15 January 20268.9M+10.5%3.3M2.72
    31 December 20258.0M-6.8%4.3M1.88
    15 December 20258.6M-3.1%1.5M5.66
    28 November 20258.9M+13.3%1.2M7.17
    14 November 20257.8M+9.6%1.5M5.33
    31 October 20257.1M-17.8%1.3M5.63
    15 October 20258.7M+13.6%1.4M6.16
    30 September 20257.7M-3.7%2.0M3.89
    15 September 20257.9M-4.5%1.5M5.15
    29 August 20258.3M-1.0%1.2M6.78
    15 August 20258.4M+10.0%1.7M4.85
    31 July 20257.6M-13.2%2.6M2.97
    15 July 20258.8M+29.1%3.5M2.49
    30 June 20256.8M+12.2%1.0M6.77
    13 June 20256.1M+9.6%1.2M5.12
    30 May 20255.5M-5.9%1.0M5.53
    15 May 20255.9M+6.4%1.0M5.70
    30 April 20255.5M+1.5%885K6.26
    15 April 20255.5M+20.6%1.1M4.84
    31 March 20254.5M-6.0%686K6.60
    14 March 20254.8M+4.9%795K6.06
    28 February 20254.6M+7.1%718K6.39
    14 February 20254.3M+2.9%692K6.19
    31 January 20254.2M-2.0%752K5.54
    15 January 20254.3M+5.8%1.3M3.30
    31 December 20244.0M+8.1%874K4.60
    13 December 20243.7M+9.9%649K5.73
    29 November 20243.4M+1.0%580K5.83
    15 November 20243.3M+5.2%1.1M2.94
    31 October 20243.2M+0.5%557K5.71
    15 October 20243.2M+9.6%688K4.60
    30 September 20242.9M-20.1%602K4.79
    13 September 20243.6M+3.0%577K6.26
    30 August 20243.5M-8.8%682K5.15
    15 August 20243.8M-9.0%899K4.28
    31 July 20244.2M-3.1%645K6.56
    15 July 20244.4M+3.0%760K5.74
    28 June 20244.2M-16.0%1.2M3.52
    14 June 20245.0M+12.9%1.1M4.54
    31 May 20244.5M+2.9%737K6.06
    15 May 20244.3M-6.7%786K5.52
    30 April 20244.7M+6.1%682K6.82
    15 April 20244.4M+11.8%739K5.93
    28 March 20243.9M+3.6%553K7.08
    15 March 20243.8M-2.2%778K4.86
    29 February 20243.9M+8.7%751K5.15
    15 February 20243.6M+4.2%628K5.67
    31 January 20243.4M-17.1%889K3.84
    12 January 20244.1M+1.4%911K4.52
    29 December 20234.1M+21.6%653K6.21
    15 December 20233.3M+3.1%891K3.75
    30 November 20233.2M-7.5%669K4.84
    15 November 20233.5M-15.9%850K4.12
    31 October 20234.2M+24.7%1.7M2.40
    13 October 20233.3M-15.0%891K3.75
    29 September 20233.9M+15.7%694K5.66
    15 September 20233.4M-1.5%699K4.86
    31 August 20233.4M-1.8%518K6.66
    15 August 20233.5M-1.1%640K5.49
    31 July 20233.6M-10.4%423K8.41
    14 July 20234.0M+6.5%455K8.72
    30 June 20233.7M+22.0%678K5.49
    15 June 20233.1M-3.9%575K5.31
    31 May 20233.2M-9.1%735K4.32
    15 May 20233.5M+17.3%711K4.91
    28 April 20233.0M+4.2%708K4.21
    14 April 20232.9M-8.2%628K4.55
    31 March 20233.1M+4.5%540K5.77
    15 March 20233.0M-3.5%557K5.34
    28 February 20233.1M-6.2%553K5.58
    15 February 20233.3M-3.4%517K6.36
    31 January 20233.4M-4.7%646K5.27
    13 January 20233.6M+6.2%726K4.92
    30 December 20223.4M-1.1%662K5.08
    15 December 20223.4M+14.1%869K3.92
    30 November 20223.0M-1.4%767K3.88
    15 November 20223.0M+2.0%835K3.62
    31 October 20223.0M-8.7%708K4.19
    14 October 20223.2M+5.9%961K3.38
    30 September 20223.1M-1.9%607K5.04
    15 September 20223.1M+6.5%575K5.43
    31 August 20222.9M-3.8%721K4.07
    15 August 20223.0M+7.5%662K4.61
    29 July 20222.8M-5.0%1.1M2.47
    15 July 20223.0M+3.1%514K5.81
    30 June 20222.9M+7.3%575K5.03
    15 June 20222.7M+0.4%518K5.21
    31 May 20222.7M-11.1%684K3.93
    13 May 20223.0M-1.4%635K4.75
    29 April 20223.1M+6.1%431K7.11
    14 April 20222.9M+2.4%534K5.41
    31 March 20222.8M-3.9%401K7.03
    15 March 20222.9M-3.0%344K8.54
    28 February 20223.0M-8.5%371K8.16
    15 February 20223.3M-4.9%490K6.74
    31 January 20223.5M-0.3%384K9.05
    14 January 20223.5M+0.6%458K7.61
    31 December 20213.5M-11.6%385K9.01
    15 December 20213.9M-1.4%526K7.45
    30 November 20214.0M-2.5%377K10.55
    15 November 20214.1M+10.2%358K11.38
    29 October 20213.7M-4.0%423K8.74
    15 October 20213.9M-3.9%367K10.51
    30 September 20214.0M+3.8%408K9.82
    15 September 20213.9M-3.9%370K10.43
    31 August 20214.0M-0.7%377K10.66
    13 August 20214.0M-0.6%565K7.16
    30 July 20214.1M+3.1%386K10.55
    15 July 20213.9M+4.4%470K8.39
    30 June 20213.8M-23.5%1.3M2.92
    15 June 20214.9M-2.7%557K8.87
    28 May 20215.1M-0.8%382K13.31
    14 May 20215.1M-6.1%526K9.74
    30 April 20215.5M+1.1%296K18.44
    15 April 20215.4M-2.0%370K14.59
    31 March 20215.5M-0.5%451K12.21
    15 March 20215.5M-5.6%377K14.68
    26 February 20215.9M+10.5%381K15.40
    12 February 20215.3M-0.4%323K16.42
    29 January 20215.3M-3.3%371K14.34
    15 January 20215.5M-5.4%546K10.09
    31 December 20205.8M-7.5%586K9.94
    15 December 20206.3M-4.2%418K15.05
    30 November 20206.6M-3.8%251K26.23
    13 November 20206.8M-3.4%553K12.35
    30 October 20207.1M-4.3%467K15.14
    15 October 20207.4M+5.4%312K23.72
    30 September 20207.0M+1.8%315K22.23
    15 September 20206.9M+1.6%363K18.97
    31 August 20206.8M-0.9%230K29.46
    14 August 20206.8M-14.7%273K25.04
    31 July 20208.0M+0.1%343K23.41
    15 July 20208.0M+4.5%491K16.34
    30 June 20207.7M+3.4%612K12.53
    15 June 20207.4M-2.3%371K19.99
    29 May 20207.6M+0.9%512K14.83
    15 May 20207.5M+1.3%458K16.45
    30 April 20207.4M+0.1%537K13.84
    15 April 20207.4M-1.1%534K13.90
    31 March 20207.5M+8.1%668K11.24
    13 March 20206.9M+6.9%478K14.53
    28 February 20206.5M+1.5%449K14.49
    14 February 20206.4M-4.2%355K18.07
    31 January 20206.7M+4.1%436K15.36
    15 January 20206.4M-1.1%824K7.80
    31 December 20196.5M+6.1%424K15.32
    13 December 20196.1M-10.9%530K11.56
    29 November 20196.9M-5.9%590K11.65
    15 November 20197.3M+14.5%517K14.14
    31 October 20196.4M+4.8%434K14.69
    15 October 20196.1M+7.2%512K11.91
    30 September 20195.7M+5.2%674K8.43
    13 September 20195.4M-6.5%1.1M5.02
    30 August 20195.8M-12.4%305K18.96
    15 August 20196.6M+6.3%458K14.39
    31 July 20196.2M+0.4%442K14.04
    15 July 20196.2M+12.9%383K16.14
    28 June 20195.5M-0.4%443K12.34
    14 June 20195.5M+9.6%383K14.32
    31 May 20195.0M+8.2%373K13.43
    15 May 20194.6M-2.7%531K8.73
    30 April 20194.8M-13.1%603K7.89
    15 April 20195.5M+1.2%444K12.32
    29 March 20195.4M-5.0%602K8.98
    15 March 20195.7M-4.8%707K8.05
    28 February 20196.0M+6.4%1.1M5.45
    15 February 20195.6M+2.5%474K11.87
    31 January 20195.5M+7.9%458K11.98
    15 January 20195.1M+1.9%749K6.78
    31 December 20185.0M+4.0%583K8.55
    14 December 20184.8M-2.4%458K10.46
    30 November 20184.9M+1.4%435K11.28
    15 November 20184.8M+10.7%602K8.04
    31 October 20184.4M-2.2%668K6.55
    15 October 20184.5M-8.4%651K6.87
    28 September 20184.9M+2.5%507K9.63
    14 September 20184.8M-0.6%434K10.97
    31 August 20184.8M-1.8%430K11.14
    15 August 20184.9M-3.6%425K11.47
    31 July 20185.1M+1.7%449K11.28
    13 July 20185.0M-1.9%386K12.88
    29 June 20185.1M-10.5%545K9.30
    15 June 20185.7M+7.9%701K8.08
    31 May 20185.3M+1.3%613K8.57
    15 May 20185.2M+4.7%497K10.44
    30 April 20185.0M-0.8%449K11.03
    13 April 20185.0M-2.9%336K14.83
    29 March 20185.1M+5.2%518K9.92
    15 March 20184.9M+2.2%447K10.94
    28 February 20184.8M+4.9%554K8.63
    15 February 20184.6M-5.4%631K7.22
    31 January 20184.8M-16.0%898K5.37
    12 January 20185.7M+4.0%410K14.01
    29 December 20175.5M384K14.38
    Shares in millions (M) or thousands (K); hold the pointer on a figure for the exact count. FINRA publishes consolidated short interest twice a month, about ten days after each settlement.