Data I/O (DAIO)

Data I/O on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders and insider trades. Listed on Nasdaq, classified by the SEC as instruments for meas & testing of electricity & elec signals.

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Short interest

settlement 2026-09-30

1.0

Days to cover

unchanged vs prior

29.3%

Short share of volume

2026-10-12

576

Fails to deliver

settlement 2026-08-20

Insider flow, 90 days

0 buys, 0 sells

As of 2026-10-12.

Short interest

FINRA, twice a month. The newest 24 settlements in the table, 48 in the chart. JSON

As of 30 September 2026, short interest in DAIO is 15,678 shares, up 12,229 shares over the last month. Over the last 48 readings it ranged from 1,133 shares (31 March 2026) to 49,635 shares (30 September 2025). At the reported average volume of 23K shares a day that is 1.0 days to cover.

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Settlement	Shares short	Change	Avg daily volume	Days to cover
2026-09-30	15,678	+132.9%	23,409	1.00
2026-09-15	6,731	+95.2%	19,469	1.00
2026-08-31	3,449	-73.7%	34,409	1.00
2026-08-14	13,129	+4.6%	46,116	1.00
2026-07-31	12,554	+69.6%	42,245	1.00
2026-07-15	7,404	+157.4%	49,084	1.00
2026-06-30	2,876	-62.8%	69,189	1.00
2026-06-15	7,721	-75.5%	91,085	1.00
2026-05-29	31,567	+6.9%	182,684	1.00
2026-05-15	29,534	+1012.8%	77,129	1.00
2026-04-30	2,654	-25.5%	34,215	1.00
2026-04-15	3,562	+214.4%	70,283	1.00
2026-03-31	1,133	-69.9%	24,681	1.00
2026-03-13	3,765	+6.4%	8,699	1.00
2026-02-27	3,538	-10.4%	38,946	1.00
2026-02-13	3,947	-53.3%	18,482	1.00
2026-01-30	8,444	-12.9%	9,784	1.00
2026-01-15	9,695	-46.8%	18,995	1.00
2025-12-31	18,239	+34.9%	35,379	1.00
2025-12-15	13,517	-25.5%	22,938	1.00
2025-11-28	18,139	-13.9%	29,865	1.00
2025-11-14	21,058	-27.2%	18,034	1.17
2025-10-31	28,914	-17.4%	33,172	1.00
2025-10-15	35,028	-29.4%	26,596	1.32

Daily short volume

FINRA Reg SHO, the last 30 sessions. JSON

As of 12 October 2026, the short share of DAIO volume is 29.3%, down 0.5 points over the last five sessions. Over the last 30 readings it ranged from 5.2% (16 September 2026) to 90.3% (6 October 2026). The latest reading is 11.2 points below the 30-session average of 40.5%, on 19K shares reported.

Date	Short volume	Total volume	Short share	Exempt
2026-10-12	6K	19K	29.3%	0
2026-10-09	13K	21K	65.0%	0
2026-10-08	4K	10K	44.5%	0
2026-10-07	6K	13K	43.4%	0
2026-10-06	9K	10K	90.3%	5,000
2026-10-05	4K	14K	29.8%	3,400
2026-10-02	4K	11K	32.7%	0
2026-10-01	9K	23K	38.3%	0
2026-09-30	12K	32K	37.0%	0
2026-09-29	2K	7K	34.4%	0
2026-09-28	2K	5K	52.0%	0
2026-09-25	1K	7K	17.8%	0
2026-09-24	1K	3K	44.1%	0
2026-09-23	2K	4K	39.5%	0
2026-09-22	1K	5K	32.9%	0
2026-09-21	1K	8K	14.7%	0
2026-09-18	2K	3K	61.0%	0
2026-09-17	12K	15K	78.3%	0
2026-09-16	2K	37K	5.2%	0
2026-09-15	1K	3K	29.9%	0
2026-09-14	3K	25K	11.4%	0
2026-09-11	3K	4K	72.6%	0
2026-09-10	2K	6K	42.2%	0
2026-09-09	6K	10K	59.5%	0
2026-09-08	5K	15K	33.1%	0
2026-09-04	1K	6K	16.2%	0
2026-09-03	5K	13K	42.2%	0
2026-09-02	2K	8K	29.1%	0
2026-09-01	3K	11K	25.3%	0
2026-08-31	7K	12K	63.5%	0

Fails to deliver

SEC, the last 30 settlement dates with a fail. JSON

As of 20 August 2026, the fails-to-deliver balance in DAIO is 576 shares, up 513 shares over the last settlement date. Over the last 30 readings it ranged from 12 shares (4 May 2026) to 5,012 shares (29 December 2025).

Settlement	Shares failed	Price	Value
2026-08-20	576	$2.88	$2K
2026-06-24	63	$3.85	$243
2026-05-04	12	$2.76	$33
2026-04-17	1,206	$2.62	$3K
2026-04-16	371	$2.51	$931
2026-03-19	332	$2.59	$860
2026-02-25	136	$2.81	$382
2026-02-18	788	$2.83	$2K
2026-02-12	681	$3.08	$2K
2026-02-04	51	$3.19	$163
2026-02-03	316	$3.09	$976
2026-02-02	703	$3.10	$2K
2026-01-30	573	$3.14	$2K
2026-01-26	92	$3.20	$294
2026-01-23	147	$3.22	$473
2026-01-16	4,137	$3.30	$14K
2026-01-14	3,978	$3.02	$12K
2026-01-13	502	$3.19	$2K
2026-01-07	121	$3.12	$378
2026-01-05	3,500	$3.30	$12K
2026-01-02	3,758	$3.17	$12K
2025-12-30	1,014	$3.38	$3K
2025-12-29	5,012	$3.22	$16K
2025-12-22	383	$2.99	$1K
2025-12-17	37	$3.11	$115
2025-12-15	819	$3.13	$3K
2025-12-11	2,297	$3.13	$7K
2025-12-08	4,230	$2.97	$13K
2025-12-04	420	$2.80	$1K
2025-11-28	244	$2.80	$683

Insider trades

SEC Form 4, newest first, 50 of 100 shown. JSON

No open-market insider trades were reported for DAIO in the last 90 days. The most recent filings are listed below. Latest filing: DiBona Charles Joseph (Vice President & CFO) on 2026-09-01.

Date	Insider	Title	Type	Shares	Price	Value	Owned after
2026-09-01	DiBona Charles Joseph	Vice President & CFO	Tax withholding	10K	$2.88	$30K	90K
2026-07-08	Larson Garrett Riley	Director	Grant	16K	$3.56	$58K	47K
2026-07-08	SMITH EDWARD J	Director	Grant	16K	$3.56	$58K	79K
2026-07-08	Washlow Sally A.	Director	Grant	16K	$3.56	$58K	89K
2026-07-08	WASZAK STEVEN M	Director	Grant	16K	$3.56	$58K	24K
2025-12-03	WASZAK STEVEN M	Director	Grant	8K	$2.79	$22K	8K
2025-12-03	Wentworth William O.	President	Grant	1K	$2.80	$3K	54K
2025-12-02	Wentworth William O.	President	Grant	7K	$2.78	$21K	53K
2025-09-01	DiBona Charles Joseph	Vice President & CFO	Grant	100K	$3.15	$315K	100K
2025-05-15	Washlow Sally A.	Director	Grant	20K	$2.48	$50K	73K
2025-05-15	Brown Douglas Wells	Director	Grant	20K	$2.48	$50K	102K
2025-05-15	Larson Garrett Riley	Director	Grant	20K	$2.48	$50K	31K
2025-05-15	SMITH EDWARD J	Director	Grant	20K	$2.48	$50K	63K
2025-05-07	SMITH EDWARD J	Director	Buy	5K	$2.46	$12K	43K
2025-05-06	Wentworth William O.	President	Buy	10K	$2.42	$25K	45K
2025-05-02	Wentworth William O.	President	Grant	11K	$2.36	$25K	35K
2025-05-01	Wentworth William O.	President	Buy	11K	$2.36	$25K	35K
2025-01-23	Larson Garrett Riley	Director	Grant	5K	$2.91	$15K	5K
2024-08-26	Brown Douglas Wells	Director	Buy	3K	$2.66	$8K	81K
2024-07-03	Ng Gerald Yat	Vice President CFO	Tax withholding	6K	$2.79	$16K	88K
2024-06-01	Ambrose Anthony	President	Grant	38K	$2.87	$108K	471K
2024-06-01	Ambrose Anthony	President	Tax withholding	9K	$2.87	$25K	434K
2024-06-01	Ambrose Anthony	President	Tax withholding	10K	$2.87	$29K	442K
2024-06-01	Ambrose Anthony	President	Tax withholding	7K	$2.87	$19K	452K
2024-06-01	Ng Gerald Yat	Vice President CFO	Grant	19K	$2.87	$54K	94K
2024-06-01	Tidwell Michael R	VP Mktg & Corp Bus Dev	Tax withholding	2K	$2.87	$6K	139K
2024-06-01	Tidwell Michael R	VP Mktg & Corp Bus Dev	Tax withholding	2K	$2.87	$6K	135K
2024-06-01	Tidwell Michael R	VP Mktg & Corp Bus Dev	Grant	13K	$2.87	$36K	148K
2024-06-01	Tidwell Michael R	VP Mktg & Corp Bus Dev	Tax withholding	2K	$2.87	$5K	137K
2024-06-01	Gulati Rajeev	Vice President CTO	Grant	13K	$2.87	$36K	168K
2024-06-01	Gulati Rajeev	Vice President CTO	Tax withholding	2K	$2.87	$6K	155K
2024-06-01	Gulati Rajeev	Vice President CTO	Tax withholding	2K	$2.87	$5K	157K
2024-06-01	Gulati Rajeev	Vice President CTO	Tax withholding	1K	$2.87	$4K	159K
2024-05-18	Tidwell Michael R	Vice President Mktg & Bus Dev	Tax withholding	3K	$2.91	$9K	141K
2024-05-18	Gulati Rajeev	Vice President CTO	Tax withholding	2K	$2.91	$6K	161K
2024-05-18	Ambrose Anthony	President	Tax withholding	10K	$2.91	$29K	459K
2024-05-16	Washlow Sally A.	Director	Grant	14K	$2.93	$41K	52K
2024-05-16	Brown Douglas Wells	Director	Grant	14K	$2.93	$41K	78K
2024-05-16	SMITH EDWARD J	Director	Grant	14K	$2.93	$41K	38K
2024-05-16	Wentworth William O.	Director	Grant	14K	$2.93	$41K	25K
2024-05-14	Ambrose Anthony	President	Gift	8K	$2.95	$22K	469K
2023-07-03	Ng Gerald Yat	Vice President Finance	Grant	75K	$4.36	$327K	75K
2023-06-01	Gulati Rajeev	Vice President CTO	Grant	20K	$4.35	$87K	163K
2023-06-01	Gulati Rajeev	Vice President CTO	Tax withholding	2K	$4.35	$9K	143K
2023-06-01	Gulati Rajeev	Vice President CTO	Tax withholding	2K	$4.35	$7K	145K
2023-06-01	HATLEN JOEL S	Vice President CFO COO	Tax withholding	2K	$4.35	$8K	180K
2023-06-01	HATLEN JOEL S	Vice President CFO COO	Tax withholding	2K	$4.35	$10K	178K
2023-06-01	Ambrose Anthony	President	Tax withholding	9K	$4.35	$41K	417K
2023-06-01	Ambrose Anthony	President	Tax withholding	6K	$4.35	$27K	426K
2023-06-01	Ambrose Anthony	President	Grant	60K	$4.35	$261K	477K

Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.

Large holders (13D and 13G)

One row per reporting person with its latest filing, newest first. JSON

2 holders report 5% or more of DAIO in their latest filing, all on Schedule 13G (passive). The largest reported stake is LYTTON LAURENCE W at 9.9% of the class (1,026,424 shares), filed 2026-06-23 for an event on 2026-06-17.

Filed	Form	Holder	Shares	Of class	Event
2026-06-23	13G	LYTTON LAURENCE Windividual	1.0M	9.9%	2026-06-17
2026-06-23	13G	Lytton-Kambara Foundationindividual	590K	5.8%	2026-06-17
2026-06-23	13G	AWL Family LLCindividual	300K	2.9%	2026-06-17
2026-02-12	13G/Ano. 7	Renaissance Technologies LLCinvestment adviser	438K	4.7%	2025-12-31
2026-02-12	13G/Ano. 7	Renaissance Technologies Holdings Corporationparent holding company	438K	4.7%	2025-12-31

13F holders

Tracked managers holding DAIO at their latest 13F. JSON

2 of the 30 tracked managers held DAIO at their latest 13F, $1.9M in total at quarter-end prices. Renaissance Technologies is the largest at $1.5M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 1 added shares and 1 cut.

Fund	Quarter	Shares	Value	Of portfolio	Change in shares
Renaissance Technologies	2026-06-30	392K	$1.5M	0.00%	-15K
Citadel Advisors	2026-06-30	87K	$342K	0.00%	new

Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.

What this page is

Data I/O in the regulatory record

Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.

Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.

This page follows Data I/O (DAIO), SEC CIK 351998, listed on Nasdaq, classified by the SEC as instruments for meas & testing of electricity & elec signals. The cross-market tables live on the short interest and insider transactions hubs.

Source and updates

Short interest: FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-09-30.JSON and CSV
Daily short volume: FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-10-12.JSON and CSV
Fails to deliver: SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-08-20.JSON and CSV
Large holders: SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-06-23.JSON and CSV
13F holders: SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
Insider trades: SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-09-01.JSON and CSV
Company record: EDGAR filing index for CIK 351998Ticker, name and exchange from the SEC's company list, refreshed weekly.
Rate limits: 10 requests a minute without a key, 30 with a free key from a free account.

How to read it

Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.

Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.

Other companies the SEC classifies as instruments for meas & testing of electricity & elec signals

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Datasets

Frequently Asked Questions

How much of DAIO is sold short?

15,678 shares were held short at the 2026-09-30 settlement, 1.0 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.

What is DAIO's daily short volume?

On 2026-10-12, 5,514 of the 18,815 DAIO shares reported to FINRA were sold short, 29.3% of the day's reported volume. Short volume is a flow for one day, not a position.

Does DAIO have fails to deliver?

The SEC's latest file shows 576 DAIO shares failed to deliver at settlement 2026-08-20. Fails are reported per settlement date and published twice a month with a lag.

Are DAIO insiders buying or selling?

No open-market insider trades were reported for DAIO in the last 90 days. The most recent filings are listed below. Latest filing: DiBona Charles Joseph (Vice President & CFO) on 2026-09-01.

Who owns 5% or more of DAIO?

Which tracked 13F managers own DAIO?

2 of the 30 tracked 13F managers held DAIO shares at their latest filing, $1.9M in all. The largest: Renaissance Technologies (392K shares, $1.5M), Ken Griffin's Citadel Advisors (87K shares, $342K).

Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.