GBDC · IV Rank History
Golub Capital BDC, Inc.
IV rank shows where GBDC's implied volatility sits within its own recent range: 0 is the lowest reading in the window, 100 the highest. This page gives the 52-week version, the 90-session version our screeners use, the IV percentile, and the daily history.
GBDC's 30-day at-the-money implied volatility was 32.4% as of Oct 22, 2026. Its 52-week IV rank is 13 and its IV percentile is 38%: IV was lower on 38% of the past year's sessions. Over those 52 weeks it ranged from 18.2% (Dec 11, 2025) to 124.5% (Oct 7, 2025). On the 90-session window our screeners use, the IV rank is 16.
GBDC IV rank history
504 sessionsFilled line: 90-session IV rank (0–100, left axis). Dashed line: 30-day at-the-money implied volatility (right axis).
GBDC IV rank and implied volatility as of 2026-10-22
How these are measured. Implied volatility here is GBDC's 30-day at-the-money IV: the implied volatility of the calls and puts struck nearest the share price, blended between the expirations on either side of 30 days so every reading covers the same horizon. It's the IV level options traders usually quote, and it doesn't jump when the nearest expiration rolls from a weekly to a monthly. The 7-day figure is the same measure a week out, so it reacts first to near-term events such as earnings.
52-week IV rank = (today's IV − 52-week low) ÷ (52-week high − 52-week low) × 100. IV percentile is the share of the past year's sessions that closed with lower IV than today. The 90-session IV rank applies the same rank formula to the last 90 sessions, so it reacts faster.
A high reading means GBDC options are expensive relative to their own recent history, which is common ahead of earnings or after a sharp move. It says nothing about which way the stock will go. The Vol Arb Screener ranks every tracked symbol by these measures.
GBDC implied volatility by month
| Month | Avg ATM IV | High | Low | Avg IV Rank (90-session) |
|---|---|---|---|---|
| Oct 2026 (to date) | 36.6% | 67.9% | 21.2% | 22 |
| Sep 2026 | 33.0% | 69.8% | 20.0% | 16 |
| Aug 2026 | 43.0% | 96.2% | 23.6% | 32 |
| Jul 2026 | 31.9% | 45.4% | 25.7% | 16 |
| Jun 2026 | 36.1% | 61.6% | 22.5% | 25 |
| May 2026 | 43.8% | 69.4% | 24.5% | 35 |
| Apr 2026 | 37.0% | 48.0% | 29.3% | 26 |
| Mar 2026 | 39.1% | 83.7% | 24.3% | 30 |
| Feb 2026 | 37.1% | 63.8% | 19.9% | 19 |
| Jan 2026 | 49.3% | 89.1% | 22.7% | 31 |
| Dec 2025 | 43.2% | 82.1% | 18.2% | 26 |
| Nov 2025 | 40.8% | 57.9% | 28.7% | 24 |
| Oct 2025 | 43.2% | 124.5% | 27.1% | 30 |
| Sep 2025 | 38.8% | 75.7% | 15.6% | 41 |
| Aug 2025 | 26.6% | 47.2% | 15.3% | 22 |
| Jul 2025 | 26.0% | 68.7% | 14.2% | 22 |
| Jun 2025 | 32.5% | 58.9% | 16.5% | 32 |
| May 2025 | 28.3% | 62.1% | 16.2% | 26 |
| Apr 2025 | 41.6% | 70.8% | 14.1% | 48 |
| Mar 2025 | 33.6% | 72.5% | 13.3% | 38 |
| Feb 2025 | 33.6% | 53.9% | 19.6% | 41 |
| Jan 2025 | 26.5% | 56.8% | 13.0% | 23 |
| Dec 2024 | 24.5% | 46.0% | 12.7% | 17 |
| Nov 2024 | 27.3% | 54.1% | 19.2% | 21 |
| Oct 2024 | 25.7% | 58.1% | 14.0% | 17 |
| Sep 2024 | 26.2% | 70.0% | 12.3% | 15 |
| Aug 2024 | 44.7% | 83.7% | 16.6% | 38 |
| Jul 2024 | 34.3% | 55.8% | 21.9% | 24 |
| Jun 2024 | 45.8% | 88.5% | 23.7% | 38 |
| May 2024 | 52.3% | 96.2% | 17.4% | 46 |
| Apr 2024 | 21.1% | 41.3% | 13.5% | 12 |
| Mar 2024 | 34.5% | 99.2% | 14.8% | 28 |
| Feb 2024 | 26.2% | 48.0% | 16.6% | 24 |
| Jan 2024 | 19.9% | 27.0% | 15.9% | 15 |
| Dec 2023 | 23.2% | 77.6% | 10.6% | 21 |
| Nov 2023 | 21.5% | 53.3% | 10.3% | 18 |
| Oct 2023 | 26.4% | 52.5% | 15.3% | 20 |
| Sep 2023 | 29.7% | 58.4% | 11.8% | 19 |
| Aug 2023 | 29.2% | 87.6% | 6.8% | 15 |
| Jul 2023 | 32.9% | 83.0% | 19.1% | 12 |
| Jun 2023 | 35.3% | 66.1% | 20.8% | 13 |
| May 2023 | 43.4% | 127.9% | 25.4% | 98 |
GBDC IV rank: last 30 sessions
| Date | IV Rank (90-session) | 30-Day ATM IV | 7-Day ATM IV |
|---|---|---|---|
| 2026-10-22 | 16 | 32.4% | — |
| 2026-10-21 | 45 | 54.4% | — |
| 2026-10-20 | 47 | 55.7% | — |
| 2026-10-19 | 3 | 22.2% | — |
| 2026-10-16 | 9 | 27.1% | — |
| 2026-10-15 | 2 | 21.2% | — |
| 2026-10-14 | 10 | 27.8% | 309.8% |
| 2026-10-13 | 52 | 59.3% | 262.1% |
| 2026-10-12 | 7 | 25.4% | 180.1% |
| 2026-10-09 | 47 | 55.9% | 64.4% |
| 2026-10-08 | 10 | 27.6% | 61.1% |
| 2026-10-07 | 63 | 67.9% | 123.6% |
| 2026-10-06 | 19 | 34.5% | 73.3% |
| 2026-10-05 | 7 | 25.4% | 42.3% |
| 2026-10-02 | 6 | 24.2% | 33.0% |
| 2026-10-01 | 6 | 24.4% | 26.2% |
| 2026-09-30 | 7 | 25.6% | 33.3% |
| 2026-09-29 | 6 | 24.2% | 23.2% |
| 2026-09-28 | 8 | 26.3% | 24.6% |
| 2026-09-25 | 5 | 23.5% | 22.5% |
| 2026-09-24 | 1 | 20.9% | — |
| 2026-09-23 | 4 | 22.7% | — |
| 2026-09-22 | 6 | 24.3% | — |
| 2026-09-21 | 4 | 23.1% | — |
| 2026-09-18 | 25 | 39.1% | — |
| 2026-09-17 | 3 | 22.1% | — |
| 2026-09-16 | 3 | 22.2% | 34.6% |
| 2026-09-15 | 0 | 20.0% | 28.1% |
| 2026-09-14 | 7 | 27.8% | 119.4% |
| 2026-09-11 | 11 | 30.8% | 78.8% |
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.