Taken at face value, Crunchbase’s tables (see below from https://www.crunchbase.com/organ…) are illuminating because they show Theranos investors can be split into two groups, early ones who started by investing modestly in 2004, increasing to more weighty numbers by 2006, and later ones who invested massive amounts ranging from US $50 to >$300 million from 2010 to 2015. They also offer additional names like Continental Ventures, a real estate company according to the New York Times, to add to those in the AngelList web-site Quincy Grayson refers to in his answer.

Over the years, various news articles have also confirmed the names of some of the early investors.

San Francisco Business Times, Ron Leuty, August 30, 2013. Theranos: The biggest biotech you’ve never heard of – San Francisco Business Times (emphasis mine)

‘venture capitalist Pete Thomas of Redwood City’s ATA Ventures — another early Theranos investor’

New Yorker, Ken Auletta, December 14, 2014. Blood, Simpler – The New Yorker (emphasis mine)

‘Theranos has raised more than four hundred million dollars from numerous investors, including the founder of Oracle, Larry Ellison

Craig Hall of Hall Financial Group. D Magazine, Christine Perez, February 5, 2015. CEO Q&A: Craig Hall (emphasis mine)

‘Providing angel-round venture capital is a fun and exciting business for us this year. Previously “top secret,” we can now talk about Theranos, a company we first found out about in 2006. With patents now in place, Theranos is making worldwide headlines, and the last round of equity raised was at $9 billion as a pre-market valuation. In 2006, our investment was a fairly modest, low startup number-so again, we’re in a position to be lucky. More important, we invested in Theranos and others as angel-round or early-round investors not solely to make money, but because we believed in the people involved and in their ideas ideas we believe could change the world and make a difference’

The Wall Street Journal, John Carreyrou, October 16, 2015. Hot Startup Theranos Has Struggled With Its Blood-Test Technology (emphasis mine)

‘Oracle Corp. co-founder Larry Ellison and venture-capital firm Draper Fisher Jurvetson, have bought stakes in Theranos, according to data from Dow Jones VentureSource’

Inc, Kimberly Weisul, October, 2015. How Playing the Long Game Made Elizabeth Holmes a Billionaire (emphasis mine)

Jennifer Fonstad, at the time a managing director at Draper Fisher Jurvetson, was one of Holmes’s early investors’

Bloomberg, Caroline Chen, Zachary Tracer, October 15, 2015. Theranos Limits Blood Technology to a Single Test Out of 200 (emphasis mine)

‘Theranos’s venture-capital backers include DFJ, formerly known as Draper Fisher Jurvetson; ATA Ventures; and billionaire Larry Ellison’s Tako Ventures.’

Bloomberg, Caroline Chen, October 19, 2015. Early Theranos Investor Stands by Blood Testing Startup (emphasis mine)

Steve Jurvetson, whose venture firm DFJ was an early investor in Theranos Inc’

Richard Kovacevich, former CEO of Wells-Fargo. The New York Times, Reed Abelson, April 24, 2016. Theranos’s Fate Rests With a Founder Who Answers Only to Herself (emphasis mine)

‘But Mr. Kovacevich, who is also an investor, emphasized that Theranos was not a publicly held company with the same responsibilities and that the shareholders understood this’

The New York Times, Randall, Stross, April 27, 2016. Don’t Blame Silicon Valley for Theranos (emphasis mine)

‘The first million dollars that the company received was from Tim Draper, a venture capitalist who became a venture capitalist through a very un-Silicon Valley-like route: His father was one (as was his grandfather). Mr. Draper had known Ms. Holmes as a childhood neighbor and playmate. The investors that followed Mr. Draper are a motley group, at least the ones visible in S.E.C. filings: a tiny firm named ATA Ventures; Continental Properties, a real estate company; and Donald L. Lucas, whose claim to fame was having invested in Oracle Corporation early.’

Who invested those massive amounts Crunchbase lists for July 2010, Feb 2014 and March 2015?

Though this is pure speculation, we can extrapolate a plausible picture from news reports of how Elizabeth Holmes leveraged family connections (The New York Times, Reed Abelson, Julie Creswell, December 19, 2015. Theranos Founder Faces a Test of Technology, and Reputation, emphasis mine) to attract US political heavyweights onto Theranos’ original board, who then may have helped get it more investors, maybe even from overseas.

‘But when it came to fund-raising, Ms. Holmes had an ace up her sleeve: family connections.

Timothy Draper, the well-known venture capitalist, had been a neighbor when the Holmeses lived in California. The children played together. “I gave her her first million bucks to get the business going,” Mr. Draper says. “She totally blows me away with her vision.”

Another anchor investor was Don Lucas. Mr. Lucas is a godfatherlike figure in Silicon Valley who built his reputation by investing in a little start-up called Oracle. To get to Mr. Lucas, Ms. Holmes relied on an introduction from a former top banking executive who went to school with her father at Wesleyan.

Mr. Lucas, who wasn’t available for an interview, served as chairman of the Theranos board for a time and brought in Lawrence Ellison, the founder and chief executive of Oracle, as another investor.

In short order, Theranos raised more than $400 million, giving it, at one point, a valuation of $9 billion.’

Political heavyweights were first publicly reported to be on Theranos’ board in July 2013 (San Franscisco Business Times, Ron Leuty, August 30, 2013. Theranos: The biggest biotech you’ve never heard of – San Francisco Business Times, emphasis mine).

‘The company in July disclosed a makeover of its board of directors, with former Secretary of State George Shultz, Holmes and Theranos President and COO Ramesh “Sunny” Balwani as the only holdovers.

Among those who left are Robert Shapiro, the former chairman of drug company Pharmacia Corp. , venture capitalist Pete Thomas of Redwood City’s ATA Ventures — another early Theranos investor — and Channing Robertson, the recently retired Stanford chemical engineering professor who encouraged Holmes to start her company.

The new board includes former Secretary of State Henry Kissinger, a retired four-star general and former Defense Secretary William Perry.

Theranos’ connections are deep. Perry, for example, was at an April meeting between Holmes and Deputy Defense Secretary Ash Carter, who visited with Silicon Valley tech companies, according to the department’s website.

Theranos would not say whether Perry had joined the board by then.’

Note George P. Shultz, former US Secretary of State was already a Theranos board member long before this. His association with Theranos appears to date from at least 2011 (see below from Fortune, Roger Parloff, June 12, 2014. A singular board at Theranos, emphasis mine).

‘In 2011, explains company founder Elizabeth Holmes, she realized that changing the way health care is delivered in this country would require the help of great strategists.

That July she finagled an introduction to George Shultz (above), the former Secretary of State, Treasury, and Labor, at Stanford’s Hoover Institution. Shultz had held four cabinet-level positions, counting his stint as director of the Office of Management and Budget, and had also been president of engineering giant Bechtel Group and a director at biopharmaceutical company Gilead Sciences.

Their scheduled 10-minute interview lasted 2½ hours. Shultz was captivated by what Holmes’s technologies could mean for health care, but was struck also by her “purity of motivation,” he says. He joined Theranos’s board that same month.’

Some of these political heavyweights may then have tapped their old boys’ network to

a) help get Theranos more investors (maybe even from overseas?)

For example, see below a photo taken on November 18, 2013, of former US Secretary of State George P. Shultz introducing Theranos CEO Elizabeth Holmes to Lee Kuan Yew, founding father of modern Singapore (from Lee Kuan Yew hosts dinner for old friend and former US diplomat George Shultz). This was taken during a trip there that also included former US Secretary of Defense William Perry and former US Senator Sam Nunn, who were both on Theranos’ board at that time. Certainly suggestive that Theranos board members may have helped Holmes tap into a global network of deep pockets.

December 29, 2015. Hagens Berman Announces Investigation of Theranos, Inc. Relating to Representations Made to Investors

‘Between February 2014 and March 2015, Theranos reportedly sought to raise over $632 million from investors selling Series C-2 preferred shares for $17 per share, and was valued at $10 billion.’

Many of Theranos investors seem to be from outside of the biotech industry. The Economist, October 31, 2015. The fable of the unicorn (emphasis mine)

‘Only one prominent venture-capital firm, Draper Fisher Jurvetson, has invested, along with Larry Ellison, one of the founders of Oracle, an IT giant. Several of its investors are small-time players with no known expertise in the industry

b) help bring more political heavyweights onto Theranos’ board (see below from San Francisco Buisiness Times, Ron Leuty, April 16, 2014. Theranos grabs another big board name in former Sen. Bill Frist – San Francisco Business Times, emphasis mine)

‘Theranos Inc. — the little-known diagnostics company with a who’s-who board — added former Senate Majority Leader Bill Frist as a director, the company said Wednesday.

Frist joins a board that already includes former Secretaries of State Henry Kissinger and George Shultz, former Defense Secretary William Perry, retired Marine Corps general James “Mad Dog” Mattis, retired Navy admiral Gary Roughead and ex U.S. Sen. Sam Nunn’

Several law firms now have investigations underway on behalf of investors to ascertain whether Theranos violated securities laws and to help them recoup their investment.

Names of investors who pumped the massive amounts post-2010 may emerge as these progress to lawsuits and make their way through the legal process.