In the second annual Disruptor 50 list, CNBC features private companies in 27 industries—from aerospace to enterprise software to retail—whose innovations are revolutionizing the business landscape. These forward-thinking upstarts have identified unexploited niches in the marketplace that have the potential to become billion-dollar businesses, and they rushed to fill them. In the process, they are creating new ecosystems for their products and services. Unseating corporate giants is no easy feat. But we ranked those venture capital–backed companies doing the best job. Already it's hard to think of the world without them. Read more about the list ranking and the methodology.

1SpaceXThe company that wants to send you to space and colonize Mars.
2Warby ParkerTaking on the Luxottica eyewear machine.
3EtsyA big voice for small artisans.
4Motif InvestingBuilding theme-based portfolios online.
5Palantir TechnologiesSilicon Valley's CIA operative.
6GitHubCracking the code on collaboration.
7AereoThe company TV hopes will die.
8Moderna TherapeuticsReprogramming cells to fight disease.
9SpotifyThe most controversial act in music.
10UberThe 21st-century taxi service.
11ZuoraA renewal in the subscription business model.
12ChargePointPutting the gas station out of business.
13DataminrThe search for intelligence on Twitter.
14Skybox ImagingThe spy who came into the Google fold.
15StripeThe start-up challenging PayPal.
16TransferWiseGetting bankers out of the forex biz.
17Personal CapitalA 360-degree view of your finances.
18QuirkyCrowdsourcing an idea for basement tinkerers.
19Pure StoragePredicting a flash flood of data.
20WealthfrontSilicon Valley's plan to oust wealth managers.
21FullscreenYouTube's hot multichannel talent network.
22EcoMotorsTurning the engine inside out
23Shape SecurityPutting organized cybercrime out of biz.
24DropboxThe 800-pound gorilla in the cloud IPO room.
25Cool Planet Energy SystemsFrom farm to fuel
26AngelListGetting disruptors the money they need to disrupt.
27BrightRollBetting detergent ads on TV won't wash.
28YextResurrecting the Yellow Pages.
29DocuSignSign on the dotted e-line.
30ApptioA cloud-based Peter Drucker.
31NebulaA private cloud the size of a pizza box.
32PinterestThe world's bulletin board.
33Lending ClubBorrowing without banks.
34RedfinThe only real estate broker who hates commissions.
35CoinbaseThe closest thing bitcoin has to a central bank.
36Hampton Creek Foods The egg comes first; no chicken necessary.
37Bill.comMaking sure the check's never in the mail again.
38Rent The RunwayNice dress. Can I borrow it?
39NexmoHow billion-dollar start-ups text.
40FonThe Airbnb meets Uber and Aereo of Wi-Fi.
41AirbnbThe newest idea in room service: renting one.
42MongoDBSolving humongous data problems.
43OscarHealth insurance for the Obamacare era.
44Kumu NetworksA much-needed boost for wireless networks.
45BettermentRobo-advising for the masses.
46KymetaBill Gates' next potential blockbuster.
47TwilioRiding the mobile-app wave.
48SnapchatThe app for selfie photo lovers.
49KickstarterCashing in from the crowd.
50BirchboxFree samples for a price

The List

1. SpaceX - The company that wants to send you to space and colonize Mars.

2. Warby Parker - Taking on the Luxottica eyewear machine.

3. Etsy - A big voice for small artisans.

4. Motif Investing - Building theme-based portfolios online.

5. Palantir Technologies - Silicon Valley's CIA operative.

6. GitHub - Cracking the code on collaboration.

7. Aereo - The company TV hopes will die.

8. Moderna - Therapeutics Reprogramming cells to fight disease.

9. Spotify - The most controversial act in music.

10. Uber - The 21st-century taxi service.

11. Zuora - A renewal in the subscription business model.

12. ChargePoint - Putting the gas station out of business.

13. Dataminr - The search for intelligence on Twitter.

14. Skybox Imaging - The spy who came into the Google fold.

15. Stripe - The start-up challenging PayPal.

16. TransferWise - Getting bankers out of the forex biz.

17. Personal Capital - A 360-degree view of your finances.

18. Quirky - Crowdsourcing an idea for basement tinkerers.

19. Pure Storage - Predicting a flash flood of data.

20. Wealthfront - Silicon Valley's plan to oust wealth managers.

21. Fullscreen - YouTube's hot multichannel talent network.

22. EcoMotors - Turning the engine inside out, in Detroit's backyard.

23. Shape Security - Putting organized cybercrime out of biz.

24. Dropbox - The 800-pound gorilla in the cloud IPO room.

25. Cool Planet Energy Systems - From farm to fuel, and back to farm.

26. AngelList - Getting disruptors the money they need to disrupt.

27. BrightRoll - Betting detergent ads on TV won't wash.

28. Yext - Resurrecting the Yellow Pages.

29. DocuSign - Sign on the dotted e-line.

30. Apptio - A cloud-based Peter Drucker.

31. Nebula - A private cloud the size of a pizza box.

32. Pinterest - The world's bulletin board.

33. Lending Club - Borrowing without banks.

34. Redfin - The only real estate broker who hates commissions.

35. Coinbase - The closest thing bitcoin has to a central bank.

36. Hampton Creek Foods - The egg comes first; no chicken necessary.

37. Bill.com - Making sure the check's never in the mail again.

38. Rent The Runway - Nice dress. Can I borrow it?

39. Nexmo - How billion-dollar start-ups text.

40. Fon - The Airbnb meets Uber and Aereo of Wi-Fi.

41. Airbnb - The newest idea in room service: renting one.

42. MongoDB - Solving humongous data problems.

43. Oscar - Health insurance for the Obamacare era.

44. Kumu Networks - A much-needed boost for wireless networks.

45. Betterment - Robo-advising for the masses.

46. Kymeta - Bill Gates' next potential blockbuster.

47. Twilio - Riding the mobile-app wave.

48. Snapchat - The app for selfie photo lovers.

49. Kickstarter - Cashing in from the crowd.

50. Birchbox - Free samples, for a price.