FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person *   Mosaic Venture Partners II Limited Partnership 2. Date of Event Requiring Statement (Month/Day/Year) 04/03/2014 3. Issuer Name and Ticker or Trading Symbol Five9, Inc. [FIVN] (Last) (First) (Middle) 6300 NORTHAM DRIVE,  4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) MISSISSAUGA, ONTARIO, A6 L4V 1H7 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock 6,307,484 D (1) Â

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Mosaic Venture Partners II Limited Partnership 6300 NORTHAM DRIVE MISSISSAUGA, ONTARIO, A6 L4V 1H7	Â	  X	Â	Â
Samuel David G. C/O BIRCH HILL EQUITY PARTNERS 100 WELLINGTON ST, W. SUITE 2300, PO BOX 22 TORONTO, ONTARIO, A6 M5K 1A1	Â	  X	Â	Â
1369904 Ontario, Inc. C/O MOSAIC VENTURE PARTNERS II, L.P. 6300 NORTHAM DRIVE MISSISSAUGA, ONTARIO, A6 L4V 1H7	Â	  X	Â	Â
Lobo Vernon F C/O MOSAIC VENTURE PARTNERS II, L.P. 6300 NORTHAM DRIVE MISSISSAUGA, ONTARIO, A6 L4V 1H7	Â	  X	Â	Â

Signatures

/s/ Vernon Lobo, authorized signatory of 1369904 Ontario Inc., the general partner of the Reporting Person		04/03/2014
**Signature of Reporting Person		Date
/s/ Frances Dea, attorney-in-fact		04/03/2014
**Signature of Reporting Person		Date
/s/ Vernon Lobo, authorized signatory of the Reporting Owner		04/03/2014
**Signature of Reporting Person		Date
/s/ Vernon Lobo		04/03/2014
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Mosaic Venture Partners II, Limited Partnership ("Mosaic") is the record owners of these shares. 1369904 Ontario, Inc. ("Ontario"), as the general partner of Mosaic, has voting and investment control of the shares held by Mosaic. David Samuel and Vernon Lobo are Managing Directors of Ontario and may be deemed to share voting and investment power with respect to the shares held by Mosaic. Mr. Samuel and Mr. Lobo disclaim beneficial ownership of all shares held by Mosaic except to the extent of their pecuniary interest therein.
  Remarks: Exhibit List Exhibit 24 - Limited Power of Attorney

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