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Exhibit 10.72

THIRD LOAN MODIFICATION AGREEMENT

        This Third Loan Modification Agreement (this "Loan Modification
Agreement") is entered into as of January 4, 2005, by and between SILICON VALLEY
BANK, a California-chartered bank, with its principal place of business at
3003 Tasman Drive, Santa Clara, California 95054 and with a loan production
office located at One Newton Executive Park, Suite 200, 2221 Washington Street,
Newton, Massachusetts 02462, doing business under the name "Silicon Valley East"
("Bank") and IBASIS, INC., a Delaware corporation with its chief executive
office located at 20 Second Avenue, Burlington, Massachusetts 01803
("Borrower").

1.    DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS.    Among other
indebtedness and obligations which may be owing by Borrower to Bank, Borrower is
indebted to Bank pursuant to a loan arrangement dated as of December 29, 2003
evidenced by, among other documents, instruments and agreements, a certain
Amended and Restated Loan and Security Agreement dated as of December 29, 2003,
as affected and amended by a certain Consent, Waiver and Amendment Agreement
dated as of June 18, 2004, as further amended by a certain First Loan
Modification Agreement dated as of June 30, 2004, and as further amended by a
certain Second Loan Modification Agreement dated as of September 30, 2004 (as
amended, the "Loan Agreement"). Capitalized terms used but not otherwise defined
herein shall have the same meaning as in the Loan Agreement.

2.    DESCRIPTION OF COLLATERAL.    Repayment of the Obligations is secured by
the Collateral as described in the Loan Agreement and is secured by the
Intellectual Property Collateral as described in a certain Intellectual Property
Security Agreement dated December 30, 2002 (the "IP Security Agreement")
(together with any other collateral security granted to Bank, the "Security
Documents").

Hereinafter, the Security Documents, together with all other documents
evidencing or securing the Obligations shall be referred to as the "Existing
Loan Documents".

3.    DESCRIPTION OF CHANGE IN TERMS.

        Modifications to Loan Agreement

1The Loan Agreement shall be amended by deleting the following, appearing as
Section 2.1.1(a) thereof, in its entirety:

"(a)    Availability.    Bank shall make Advances to Borrower not exceeding
(i) the lesser of (A) the Revolving Line or (B) the Borrowing Base, minus
(ii) the amount of all outstanding Letters of Credit (including drawn but
unreimbursed Letters of Credit), minus (iii) the FX Reserve, and minus (iv) the
aggregate outstanding Advances hereunder (including any Cash Management
Services). Amounts borrowed under this Section may be repaid and reborrowed
during the term of this Agreement."

and inserting in lieu thereof the following:

"(a)    Availability.    Bank shall make Advances to Borrower not exceeding (i)
the Revolving Line, minus (ii) the amount of all outstanding Letters of Credit
(including drawn but unreimbursed Letters of Credit), minus (iii) the FX
Reserve, and minus (iv) the aggregate outstanding Advances hereunder (including
any Cash Management Services). Amounts borrowed under this Section may be repaid
and reborrowed during the term of this Agreement."

2The Loan Agreement shall be amended by deleting the following text, appearing
in Section 2.3(a) thereof, in its entirety:

"(a)    Interest Rate.    The principal amounts outstanding under the Revolving
Line shall accrue interest at a per annum rate equal to the aggregate of the
Prime Rate plus one percent (1.0%)."

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and inserting in lieu thereof the following:

"(a)    Interest Rate.    The principal amounts outstanding under the Revolving
Line shall accrue interest at a per annum rate equal to the Prime Rate plus
one-half of one percent (0.5%)."

3The Loan Agreement shall be amended by deleting the following, appearing as
Section 2.3(d) thereof, in its entirety:

"(d)    Revolving Line Clean-Up.    Without notice or demand by Bank, Borrower
shall repay all Advances (not to include the face amount of any issued but
undrawn Letters of Credit) maintaining a zero dollar ($0.00) balance for a
period of forty-five (45) consecutive days during each calendar quarter during
the term hereof, and not request additional Advances during such forty-five (45)
day period."

and inserting in lieu thereof the following:

"(d)    Intentionally Omitted."

4The Loan Agreement shall be amended by inserting the following after
Section 2.4(d):

"(e)    Compensating Balance/Compensating Balances Fees.    In the event, at any
time, Borrower maintains less than Fifteen Million Dollars ($15,000,000.00) in
unrestricted cash or cash equivalents with Bank, Borrower shall pay such fees
and expenses as Bank shall determine, in its reasonable discretion, to
compensate Bank for its loss on income on such deposit balance."

5The Loan Agreement shall be amended by deleting the following, appearing as
Section 6.2(b) thereof, in its entirety:

"(b)    Within fifteen (15) days after the last day of each month, Borrower
shall deliver to Bank a Borrowing Base Certificate signed by a Responsible
Officer in the form of Exhibit C, with aged listings of accounts receivable (by
invoice date)."

and inserting in lieu thereof the following:

"(b)    Within thirty (30) days after the last day of Borrower's fiscal year,
Borrower shall deliver to Bank a budget for Borrower's next fiscal year in form
satisfactory to Bank, in its reasonable discretion."

6The Loan Agreement shall be amended by deleting Section 6.7 in its entirety and
inserting in lieu thereof the following:

"6.7    Financial Covenants.

(a)    Adjusted Quick Ratio.    Borrower shall have, at all times, to be tested
as of the last day of each month through and including the month ending
January 31, 2006, and as of the last day of calendar quarter thereafter, an
Adjusted Quick Ratio of:

(i)1.25 to 1.0, from December 31, 2004 through December 31, 2005;

and

(ii)1.50 to 1.0 thereafter.

(b)    Maximum Net Loss.    Borrower shall have maximum quarterly net loss as
follows:

(i)($5,000,000.00) for the quarter ending December 31, 2004;

(ii)($4,000,000.00) for the quarter ending March 31, 2005;

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(iii)($3,000,000.00) for the quarter ending June 30, 2005; and

(iv)($2,000,000.00) for the quarter ending September 30, 2005.

(c)    Minimum Net Profit.    Borrower shall have minimum quarterly net profit
equal to the greater of either (i) One Dollar ($1.00) or (ii) fifty percent
(50%) of Borrower's board of directors approved plan, to be tested as of
December 31, 2005 and as of the last day of each calendar quarter thereafter."

7The Loan Agreement shall be amended by deleting the following definitions
appearing in Section 13.1 thereof:

"        "Prime Rate" is the greater of (i) four percent (4.0%) or (ii) Bank's
most recently announced "prime rate," even if it is not Bank's lowest rate.

        "Revolving Maturity Date" is January 5, 2005."

and inserting in lieu thereof the following:

"        "Prime Rate" is the greater of either (i) five and one-quarter of one
percent (5.25%) or (ii) Bank's most recently announced "prime rate," even if it
is not Bank's lowest rate.

        "Revolving Maturity Date" is January 31, 2007."

8The Loan Agreement shall be amended by adding the following definitions, in
alphabetical order, in Section 13.1 thereof:

"        "Adjusted Quick Ratio" is the ratio of (i) Quick Assets to (ii) Current
Liabilities minus Deferred Revenue.

        "Current Liabilities" are all obligations and liabilities of Borrower to
Bank, plus, without duplication, the aggregate amount of Borrower's Total
Liabilities which mature within one (1) year.

        "Quick Assets" is, on any date, the Borrower's consolidated,
unrestricted cash, unrestricted cash equivalents, plus net accounts receivable.

        "Total Liabilities" is on any day, obligations that should, under GAAP,
be classified as liabilities on Borrower's consolidated balance sheet, including
all Indebtedness."

9The Borrowing Base Certificate appearing as Exhibit C is hereby deleted from
the Loan Agreement.

4.    FEES.    Borrower shall pay to Bank a modification fee equal to
Fifty-Seven Thousand Five Hundred Dollars ($57,500.00), which fee shall be
earned as of the date hereof and shall be payable as follows: (i) Thirty-Two
Thousand Five Hundred Dollars ($32,500.00) on the date hereof and
(ii) Twenty-Five Thousand dollars ($25,000.00) on the sooner to occur of (x) the
occurrence of an Event of Default, (y) the early termination of the Loan
Agreement, or (z) January 5, 2006. Borrower shall also reimburse Bank for all
reasonable legal fees and expenses incurred in connection with this amendment to
the Existing Loan Documents.

5.    RATIFICATION OF IP SECURITY AGREEMENT.    Borrower hereby ratifies,
confirms and reaffirms, all and singular, the terms and conditions of the IP
Security Agreement, and acknowledges, confirms and agrees that the IP Security
Agreement contains an accurate and complete (in all material respects) listing
of all Intellectual Property Collateral as defined therein, and shall remain in
full force and effect.

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6.    RATIFICATION OF PERFECTION CERTIFICATE.    Borrower hereby ratifies,
confirms and reaffirms, all and singular, the terms and disclosures contained in
a certain Perfection Certificate dated as of December 30, 2002 between Borrower
and Bank, and acknowledges, confirms and agrees the disclosures and information
Borrower provided to Bank in the Perfection Certificate have not changed in any
material respects, as of the date hereof.

7.    CONSISTENT CHANGES.    The Existing Loan Documents are hereby amended
wherever necessary to reflect the changes described above.

8.    NO DEFENSES OF BORROWER.    Borrower hereby acknowledges and agrees that
Borrower has no offsets, defenses, claims, or counterclaims against Bank with
respect to the Obligations, or otherwise, and that if Borrower now has, or ever
did have, any offsets, defenses, claims, or counterclaims against Bank, whether
known or unknown, at law or in equity, all of them are hereby expressly WAIVED
and Borrower hereby RELEASES Bank from any liability thereunder, in each case to
the extent that any of the foregoing arises from any action or failure to act on
or prior to the date hereof under or in respect of the Loan Agreement or any of
the other Existing Loan Documents; provided, however, that the waiver and
release contained herein shall not apply to any act or omission constituting
gross negligence or willful misconduct on behalf of Bank which is discovered by
Borrower after the date hereof.

9.    CONTINUING VALIDITY.    Borrower understands and agrees that in modifying
the existing Obligations, Bank is relying upon Borrower's representation,
warranties, and agreements, as set forth in the Existing Loan Documents. Except
as expressly modified pursuant to this Loan Modification Agreement, the terms of
the Existing Loan Documents remain unchanged and in full force and effect and
Borrower hereby ratifies, confirms, and reaffirms all the terms and conditions
thereof. Borrower confirms that the indebtedness secured by the Security
Documents includes, without limitation, the Obligations. Bank's agreement to
modifications to the existing Obligations pursuant to this Loan Modification
Agreement in no way shall obligate Bank to make any future modifications to the
Obligations. Nothing in this Loan Modification Agreement shall constitute a
satisfaction of the Obligations. It is the intention of Bank and Borrower to
retain as liable parties all makers of Existing Loan Documents, unless the party
is expressly released by Bank in writing. No maker will be released by virtue of
this Loan Modification Agreement.

10.    COUNTERSIGNATURE.    This Loan Modification Agreement shall become
effective only when it shall have been executed by Borrower and Bank (provided,
however, in no event shall this Loan Modification Agreement become effective
until signed by an officer of Bank in California).

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        This Loan Modification Agreement is executed as a sealed instrument
under the laws of the Commonwealth of Massachusetts as of the date first written
above.

BORROWER:   BANK:
IBASIS, INC.
 
SILICON VALLEY BANK, doing business as
SILICON VALLEY EAST
By:
/s/  OFER GNEEZY      

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By:
/s/  MICHAEL D. SINCLAIR      

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Name: Ofer Gneezy

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  Name: Michael D. Sinclair

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Title: President

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  Title: Vice President

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SILICON VALLEY BANK
 
 
 
By:
/s/  JACQUELIN LE      

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      Name: Jacquelin Le

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      Title: Operations Supervisor

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(signed in Santa Clara County, California)

        The undersigned, IBASIS GLOBAL, INC., ratifies, confirms and reaffirms,
all and singular, the terms and conditions of a certain Unconditional Guaranty
dated December 29, 2003 executed and delivered by the undersigned and a certain
Security Agreement dated December 29, 2003 executed and delivered by the
undersigned and acknowledges, confirms and agrees that the said Unconditional
Guaranty and Security Agreement shall remain in full force and effect and shall
in no way be limited by the execution of this Loan Modification Agreement, or
any other documents, instruments and/or agreements executed and/or delivered in
connection herewith.

      IBASIS GLOBAL, INC.
 
 
 
By:
/s/  OFER GNEEZY      

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      Name: Ofer Gneezy       Title: President

        The undersigned, IBASIS SECURITIES CORPORATION, ratifies, confirms and
reaffirms, all and singular, the terms and conditions of a certain Unconditional
Guaranty dated December 29, 2003 executed and delivered by the undersigned and a
certain Security Agreement dated December 29, 2003 executed and delivered by the
undersigned and acknowledges, confirms and agrees that the said Unconditional
Guaranty and Security Agreement shall remain in full force and effect and shall
in no way be limited by the execution of this Loan Modification Agreement, or
any other documents, instruments and/or agreements executed and/or delivered in
connection herewith.

      IBASIS SECURITIES CORPORATION
 
 
 
By:
/s/  OFER GNEEZY      

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      Name: Ofer Gneezy       Title: President

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Exhibit 10.72

THIRD LOAN MODIFICATION AGREEMENT