Sec Form 4 Filing - Montreux Equity Partners IV, L.P. @ SI-BONE, Inc. - 2018-10-19

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP 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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1. Name and Address of Reporting Person Montreux Equity Partners IV, L.P. 2. Issuer Name and Ticker or Trading Symbol SI-BONE, Inc. [ SIBN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) ONE FERRY BUILDING, SUITE 255 3. Date of Earliest Transaction (MM/DD/YY) 10/19/2018 (Street) SAN FRANCISCO, CA94111 4. If Amendment, Date Original Filed (MM/DD/YY) 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 Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 10/19/2018 C 1,102,915 A 1,102,915 I By Montreux Equity Partners IV, L.P. ( 2 ) Common Stock 10/19/2018 C 597,071 A 1,699,986 I By Montreux Equity Partners IV, L.P. ( 2 ) Common Stock 10/19/2018 C 27,409 A 1,727,395 I By Montreux Equity Partners IV, L.P. ( 2 ) Common Stock 10/19/2018 C 78,564 A 78,564 I By Montreux IV Associates, LLC ( 2 ) Common Stock 10/19/2018 C 51,827 A 130,391 I By Montreux IV Associates, LLC ( 2 ) Common Stock 10/19/2018 C 171,929 A 171,929 I By Montreux IV Associates IV, LLC ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Warrant (right to buy) $ 9.1 10/19/2018 X 15,496 ( 4 ) ( 4 ) Series 5 Preferred Stock 15,496 $ 0 0 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 5 Preferred Stock $ 9.1 10/19/2018 X 15,496 ( 1 ) ( 1 ) Common Stock 15,496 $ 0 1,112,312 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 5 Preferred Stock ( 1 ) 10/19/2018 S( 5 ) 9,397 ( 1 ) ( 1 ) Common Stock 9,397 $ 15 1,102,915 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 5 Preferred Stock ( 1 ) 10/19/2018 C 1,102,915 ( 1 ) ( 1 ) Common Stock 1,102,915 ( 1 ) 0 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 5 Preferred Stock ( 1 ) 10/19/2018 C 78,564 ( 1 ) ( 1 ) Common Stock 78,564 ( 1 ) 0 I By Montreux IV Associates, LLC ( 2 ) Series 6 Preferred Stock ( 3 ) 10/19/2018 C 563,926 ( 3 ) ( 3 ) Common Stock 597,071 ( 3 ) 0 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 6 Preferred Stock ( 3 ) 10/19/2018 C 48,950 ( 3 ) ( 3 ) Common Stock 51,827 ( 3 ) 0 I By Montreux IV Associates, LLC ( 2 ) Series 7 Preferred Stock ( 1 ) 10/19/2018 C 27,409 ( 1 ) ( 1 ) Common Stock 27,409 ( 1 ) 0 I By Montreux Equity Partners IV, L.P. ( 2 ) Series 7 Preferred Stock ( 1 ) 10/19/2018 C 171,929 ( 1 ) ( 1 ) Common Stock 171,929 ( 1 ) 0 I By Montreux IV Associates IV, LLC ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Montreux Equity Partners IV, L.P. ONE FERRY BUILDING, SUITE 255 SAN FRANCISCO, CA94111 X Montreux IV Associates, LLC ONE FERRY BUILDING, SUITE 255 SAN FRANCISCO, CA94111 X Montreux IV Associates IV, LLC ONE FERRY BUILDING, SUITE 255 SAN FRANCISCO, CA94111 X Montreux Equity Management IV, LLC ONE FERRY BUILDING, SUITE 255 SAN FRANCISCO, CA94111 X TURNER DANIEL K III ONE FERRY BUILDING, SUITE 255 SAN FRANCISCO, CA94111 X Signatures Montreux Equity Partners IV, L.P., By: Montreux Equity Management IV, L.L.C., Its: General Partner, /s/ Daniel K. Turner III, Managing Director 10/19/2018 Signature of Reporting Person Date Montreux IV Associates, LLC, By: Montreux Equity Management IV, L.L.C., Its: General Partner, By: /s/ Daniel K. Turner III, Managing Director 10/19/2018 Signature of Reporting Person Date Montreux IV Associates IV, LLC, By: Montreux Equity Management IV, L.L.C., Its: General Partner, By: /s/ Daniel K. Turner III, Managing Director 10/19/2018 Signature of Reporting Person Date Montreux Equity Management IV, L.L.C., Its: General Partner, By: /s/ Daniel K. Turner III, Managing Director 10/19/2018 Signature of Reporting Person Date /s/ Daniel K. Turner III 10/19/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Issuer's Series 5 Preferred Stock and Series 7 Preferred Stock automatically converted into an equal number of shares of Issuer's common stock immediately upon the closing of the Issuer's initial public offering and has no expiration date. ( 2 )Montreux Equity Management IV, L.L.C. ("MEM IV LLC") is the general partner of each of Montreux Equity Partners IV, L.P., Montreux IV Associates, L.L.C and Montreux IV Associates IV, L.L.C. Daniel K. Turner III is the managing director of MEM IV LLC and may be deemed to have voting and investment power over the shares held by each of these entities. Mr. Turner disclaims beneficial ownership of such shares, except to the extent of his proportionate pecuniary interest, if any. ( 3 )The Issuer's Series 6 Preferred Stock automatically converted into approximately 1.05878 shares of Issuer's common stock immediately upon the closing of the Issuer's initial public offering and has no expiration date. ( 4 )Shares subject to the warrant are immediately exercisable. The warrant will expire in connection with the closing of the Issuer's initial public offering. ( 5 )Immediately prior to the closing of the Issuer's initial public offering, Montreux Equity Partners IV, L.P. exercised a warrant to purchase 15,496 shares of Series 5 Preferred Stock at an exercise price of $9.10 per share. The exercise price was paid on a net exercise cashless basis calculated using the Issuer's initial public offering price of $15.00, resulting in the Issuer withholding 9,397 of the warrant shares to pay the exercise price and issuing MEP the remaining 6,099 shares.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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