Cal Henderson Biography and Net Worth

CTO of Slack Technologies

Callum “Cal” Henderson is the co-founder and CTO of Slack, the world’s leading messaging platform for businesses. He oversees the company’s engineering team and sets its technical vision.

Henderson is British and holds a Bachelor of Computer Science degree as well as an honorary doctorate from Birmingham City University. He was involved in London’s early online community through his development and co-ownership of the early digital creative community, B3ta. Henderson has also authored his personal blog, iamcal.com, since 2000.

Henderson was a pioneer in the use of web APIs, and created the basis for OAuth and oEmbed, now used by YouTube, Twitter, and many others.

Prior to Slack, Henderson was the chief software architect at Flickr, where he built and led the engineering teams through its acquisition by Yahoo. He worked for EMAP as technical director of special web projects, where he wrote City Creator, among other websites, services and desktop applications.

Henderson was the co-founder and VP of engineering at Tiny Speck, where an internal communications tool ended up transitioning into what we now know as Slack.

Slack was launched in 2013 by Henderson and his co-founder Stewart Butterfield. It was developed from an internal tool used during the development of Tiny Speck’s now-defunct computer game, Glitch.

Slack went public on the New York Stock Exchange in June 2019, and in December 2020, it was acquired by Salesforce for $27.7 billion.

Henderson is color blind and has spent time working on applications that make the web more accessible to people with color blindness. He also regularly contributes to open-source software projects and operates multiple utility websites, like Unicodey, to make various programming tasks easier.

He is an experienced technology leader and a sought-after speaker on engineering scalability, having authored the best-selling O’Reilly Media book Building Scalable Websites. In 2019, he was named a Fortune 40 Under 40 honoree and recognized by the World Economic Forum as a Young Global Leader.

Henderson lives in San Francisco with his family.

What is Cal Henderson's net worth?: The estimated net worth of Cal Henderson is at least $1.80 million as of April 1st, 2021. Mr. Henderson owns 39,737 shares of Slack Technologies stock worth more than $1,796,112 as of December 23rd. This net worth estimate does not reflect any other investments that Mr. Henderson may own. Learn More about Cal Henderson's net worth.
How old is Cal Henderson?: Mr. Henderson is currently 40 years old. There are 5 older executives and no younger executives at Slack Technologies. The oldest executive at Slack Technologies is Mr. David R. Schellhase, Gen. Counsel & Corp. Sec., who is 57 years old. Learn More on Cal Henderson's age.
How do I contact Cal Henderson?: The corporate mailing address for Mr. Henderson and other Slack Technologies executives is 500 HOWARD STREET, SAN FRANCISCO CA, 94105. Slack Technologies can also be reached via phone at 415-630-7943 and via email at [email protected]. Learn More on Cal Henderson's contact information.
Has Cal Henderson been buying or selling shares of Slack Technologies?: Cal Henderson has not been actively trading shares of Slack Technologies during the last quarter. Most recently, Cal Henderson sold 1,072 shares of the business's stock in a transaction on Thursday, April 1st. The shares were sold at an average price of $41.20, for a transaction totalling $44,166.40. Following the completion of the sale, the chief technology officer now directly owns 39,737 shares of the company's stock, valued at $1,637,164.40. Learn More on Cal Henderson's trading history.
Who are Slack Technologies' active insiders?: Slack Technologies' insider roster includes Stewart Butterfield (CEO), Robert Frati (SVP), Cal Henderson (CTO), David Schellhase (General Counsel), Allen Shim (CFO), Graham Smith (Director), Tamar Yehoshua (Insider), and Brandon Zell (CAO). Learn More on Slack Technologies' active insiders.

Cal Henderson Insider Trading History at Slack Technologies

Transaction Date	Buy/Sell	Number of Shares	Average Share Price	Total Transaction	Shares Held After Transaction
4/1/2021	Sell	1,072	$41.20	$44,166.40	39,737
1/4/2021	Sell	1,252	$41.99	$52,571.48	40,809
12/7/2020	Sell	1,500	$43.07	$64,605.00	42,061
12/4/2020	Sell	1,500	$42.86	$64,290.00	42,061
12/2/2020	Sell	1,500	$42.86	$64,290.00	42,061
11/30/2020	Sell	1,500	$42.60	$63,900.00	42,061
11/27/2020	Sell	1,500	$40.03	$60,045.00	42,061
11/25/2020	Sell	1,500	$30.99	$46,485.00	42,061
11/23/2020	Sell	1,500	$30.00	$45,000.00	42,061
11/20/2020	Sell	100	$30.00	$3,000.00	42,061
10/20/2020	Sell	3,000	$31.99	$95,970.00	42,061
10/16/2020	Sell	1,500	$32.67	$49,005.00	42,061
10/14/2020	Sell	1,500	$32.45	$48,675.00	42,061
10/12/2020	Sell	1,500	$31.61	$47,415.00	42,061
10/9/2020	Sell	1,500	$30.16	$45,240.00	42,061
10/7/2020	Sell	1,500	$30.00	$45,000.00	42,061
9/8/2020	Sell	1,500	$30.01	$45,015.00	43,560
9/4/2020	Sell	1,500	$30.83	$46,245.00	43,560
9/2/2020	Sell	1,500	$33.75	$50,625.00	43,560
8/31/2020	Sell	3,000	$32.05	$96,150.00	43,560
8/27/2020	Sell	3,000	$30.27	$90,810.00	43,560
8/21/2020	Sell	3,000	$30.06	$90,180.00
8/5/2020	Sell	1,500	$30.09	$45,135.00	43,560
7/24/2020	Sell	20	$30.00	$600.00	43,560
7/22/2020	Sell	1,500	$31.58	$47,370.00	43,560
7/20/2020	Sell	1,500	$33.02	$49,530.00	43,560
7/17/2020	Sell	1,500	$31.84	$47,760.00	43,560
7/15/2020	Sell	3,000	$31.94	$95,820.00	43,560
7/13/2020	Sell	1,500	$34.91	$52,365.00	43,560
7/10/2020	Sell	1,500	$33.75	$50,625.00	43,560
7/8/2020	Sell	1,500	$33.27	$49,905.00	43,560
7/6/2020	Sell	1,500	$31.15	$46,725.00	43,560
7/2/2020	Sell	4,412	$30.73	$135,580.76
6/30/2020	Sell	3,000	$30.84	$92,520.00	44,972
6/26/2020	Sell	1,500	$32.58	$48,870.00	44,972
6/24/2020	Sell	1,500	$32.64	$48,960.00	44,972
6/22/2020	Sell	1,500	$33.72	$50,580.00	44,972
6/18/2020	Sell	3,000	$33.29	$99,870.00	44,972
6/15/2020	Sell	1,500	$30.00	$45,000.00	44,972
6/12/2020	Sell	1,500	$30.75	$46,125.00	44,972
6/10/2020	Sell	3,000	$30.34	$91,020.00	44,972
6/3/2020	Sell	1,500	$39.38	$59,070.00	44,972
6/1/2020	Sell	1,500	$35.58	$53,370.00	44,972
5/28/2020	Sell	1,500	$32.22	$48,330.00	44,972
5/26/2020	Sell	1,500	$32.00	$48,000.00	44,972
5/21/2020	Sell	1,500	$31.50	$47,250.00	44,972
5/19/2020	Sell	1,500	$30.00	$45,000.00	44,972
5/13/2020	Sell	1,500	$31.27	$46,905.00	44,972
5/11/2020	Sell	1,500	$31.00	$46,500.00	44,972
5/1/2020	Sell	13,528	$25.93	$350,781.04	58,500
4/20/2020	Sell	1,500	$30.00	$45,000.00	44,972
4/16/2020	Sell	200	$30.00	$6,000.00	44,972
3/11/2020	Sell	1,500	$24.21	$36,315.00
3/9/2020	Sell	1,500	$24.35	$36,525.00
3/6/2020	Sell	1,500	$26.57	$39,855.00
3/3/2020	Sell	1,500	$26.74	$40,110.00
2/26/2020	Sell	1,500	$26.84	$40,260.00
2/24/2020	Sell	1,500	$27.79	$41,685.00
2/19/2020	Sell	1,500	$27.76	$41,640.00
2/12/2020	Sell	1,500	$25.45	$38,175.00
2/10/2020	Sell	1,500	$25.33	$37,995.00
2/6/2020	Sell	1,500	$23.00	$34,500.00
2/4/2020	Sell	1,500	$22.84	$34,260.00
1/31/2020	Sell	1,500	$20.30	$30,450.00
1/29/2020	Sell	1,500	$20.83	$31,245.00
1/27/2020	Sell	1,500	$20.24	$30,360.00
1/23/2020	Sell	1,500	$21.57	$32,355.00
1/21/2020	Sell	1,500	$22.42	$33,630.00
1/17/2020	Sell	1,500	$22.74	$34,110.00
1/15/2020	Sell	1,500	$22.67	$34,005.00
1/13/2020	Sell	1,500	$23.22	$34,830.00
1/10/2020	Sell	1,500	$23.05	$34,575.00
1/8/2020	Sell	1,500	$23.94	$35,910.00
1/6/2020	Sell	1,500	$23.38	$35,070.00
1/3/2020	Sell	1,500	$22.65	$33,975.00
12/26/2019	Sell	1,500	$21.72	$32,580.00
12/18/2019	Sell	1,500	$21.08	$31,620.00
12/16/2019	Sell	1,500	$21.53	$32,295.00
12/13/2019	Sell	1,500	$21.10	$31,650.00
12/11/2019	Sell	1,500	$20.97	$31,455.00
12/9/2019	Sell	1,500	$22.87	$34,305.00
12/6/2019	Sell	1,500	$22.75	$34,125.00
12/4/2019	Sell	1,500	$22.02	$33,030.00
12/2/2019	Sell	1,500	$21.87	$32,805.00
11/29/2019	Sell	1,500	$22.91	$34,365.00
11/27/2019	Sell	1,500	$22.42	$33,630.00
11/25/2019	Sell	1,500	$22.07	$33,105.00
11/22/2019	Sell	1,500	$21.16	$31,740.00
11/20/2019	Sell	1,500	$21.51	$32,265.00
11/18/2019	Sell	1,500	$23.09	$34,635.00
11/14/2019	Sell	1,500	$21.32	$31,980.00
11/12/2019	Sell	1,500	$20.05	$30,075.00
11/6/2019	Sell	1,500	$20.50	$30,750.00
11/1/2019	Sell	14,809	$20.75	$307,286.75
10/30/2019	Sell	1,500	$21.95	$32,925.00
10/28/2019	Sell	1,500	$22.00	$33,000.00
10/25/2019	Sell	1,500	$23.04	$34,560.00
10/23/2019	Sell	1,500	$21.21	$31,815.00
10/21/2019	Sell	1,500	$21.12	$31,680.00
10/17/2019	Sell	1,500	$22.58	$33,870.00
10/15/2019	Sell	1,500	$24.00	$36,000.00
10/11/2019	Sell	1,500	$24.00	$36,000.00
10/8/2019	Sell	1,500	$25.05	$37,575.00
10/3/2019	Sell	1,500	$24.09	$36,135.00
9/30/2019	Sell	1,500	$23.24	$34,860.00
9/27/2019	Sell	1,500	$21.98	$32,970.00
9/25/2019	Sell	1,500	$22.26	$33,390.00
9/23/2019	Sell	1,500	$24.17	$36,255.00
9/20/2019	Sell	1,500	$25.50	$38,250.00
9/18/2019	Sell	1,500	$25.77	$38,655.00
9/16/2019	Sell	1,500	$25.21	$37,815.00
9/13/2019	Sell	1,500	$25.10	$37,650.00
9/11/2019	Sell	1,500	$25.67	$38,505.00
9/9/2019	Sell	1,500	$25.41	$38,115.00
9/5/2019	Sell	1,500	$28.79	$43,185.00
9/3/2019	Sell	1,500	$28.41	$42,615.00
8/29/2019	Sell	1,500	$29.64	$44,460.00
8/26/2019	Sell	1,500	$30.65	$45,975.00
8/22/2019	Sell	1,500	$30.96	$46,440.00
8/20/2019	Sell	1,500	$30.53	$45,795.00
8/16/2019	Sell	1,500	$30.15	$45,225.00
8/13/2019	Sell	1,500	$31.36	$47,040.00
8/9/2019	Sell	1,500	$31.05	$46,575.00
8/7/2019	Sell	1,500	$30.67	$46,005.00
8/5/2019	Sell	1,500	$29.89	$44,835.00
8/2/2019	Sell	1,500	$31.19	$46,785.00
7/31/2019	Sell	1,500	$33.20	$49,800.00
7/29/2019	Sell	1,500	$33.22	$49,830.00
7/26/2019	Sell	1,500	$33.78	$50,670.00
7/24/2019	Sell	1,500	$33.82	$50,730.00
7/22/2019	Sell	1,500	$32.56	$48,840.00
7/19/2019	Sell	1,500	$31.99	$47,985.00
7/17/2019	Sell	1,500	$33.97	$50,955.00
7/15/2019	Sell	1,500	$34.49	$51,735.00
7/12/2019	Sell	1,500	$33.96	$50,940.00
7/10/2019	Sell	1,500	$35.45	$53,175.00
7/8/2019	Sell	1,500	$35.13	$52,695.00
7/5/2019	Sell	1,500	$35.69	$53,535.00
7/2/2019	Sell	3,000	$36.70	$110,100.00
6/28/2019	Sell	1,500	$36.59	$54,885.00
6/26/2019	Sell	1,500	$36.73	$55,095.00
6/24/2019	Sell	1,500	$36.23	$54,345.00
6/21/2019	Sell	99,342	$38.62	$3,836,588.04

Cal Henderson Buying and Selling Activity at Slack Technologies

Slack Technologies Company Overview

Slack Technologies, Inc. operates Slack, a business technology software platform in the United States and internationally. Its platform brings together people, applications, and data, as well as sells its offering under a software-as-a-service model. The company was formerly known as Tiny Speck, Inc. and changed its name to Slack Technologies, Inc. in 2014. Slack Technologies, Inc. was incorporated in 2009 and is headquartered in San Francisco, California.

Today's Range

Now: $45.20

$45.20

50 Day Range

MA: $44.80

$43.97

$45.20

2 Week Range

Now: $45.20

$24.09

$45.64

Volume

N/A

Average Volume

6,639,090 shs

Market Capitalization

$26.52 billion

P/E Ratio

N/A

Dividend Yield

N/A

Beta

0.97

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Cal Henderson Biography and Net Worth

What is Cal Henderson's net worth?

How old is Cal Henderson?

How do I contact Cal Henderson?

Has Cal Henderson been buying or selling shares of Slack Technologies?

Who are Slack Technologies' active insiders?

Cal Henderson Insider Trading History at Slack Technologies

Cal Henderson Buying and Selling Activity at Slack Technologies

Slack Technologies Company Overview

Today's Range

50 Day Range

2 Week Range

Volume

Average Volume

Market Capitalization

P/E Ratio

Dividend Yield

Beta