iBasis, Inc.

DateInflation Amount Per Share*
11/10/1999**$28.7265***
11/11/1999$26.687
11/12/1999$25.9208
11/15/1999$26.7534
11/16/1999$25.9207
11/17/1999$24.5049
11/18/1999$25.0723
11/19/1999$25.8931
11/22/1999$25.2857
11/23/1999$24.3808
11/24/1999$24.2047
11/26/1999$25.2831
11/29/1999$27.9011
11/30/1999$25.4109
12/1/1999$26.6871
12/2/1999$27.3241
12/3/1999$28.0441
12/6/1999$26.7313
12/7/1999$26.7478
12/8/1999$26.4471
12/9/1999$26.5127
12/10/1999$26.2792
12/13/1999$26.6989
12/14/1999$25.3325
12/15/1999$23.7769
12/16/1999$22.9848
12/17/1999$21.2266
12/20/1999$19.5356
12/21/1999$22.2519
12/22/1999$21.5745
12/23/1999$22.9981
12/27/1999$23.6089
12/28/1999$25.1851
12/29/1999$23.8049
12/30/1999$23.8053
12/31/1999$22.1474
1/3/2000$23.5738
1/4/2000$24.47
1/5/2000$24.0285
1/6/2000$23.9465
1/7/2000$23.4173
1/10/2000$23.8741
1/11/2000$25.4912
1/12/2000$25.8795
1/13/2000$27.0133
1/14/2000$28.7265
1/18/2000$28.7265
1/19/2000$28.7265
1/20/2000$28.7265
1/21/2000$28.7265
1/24/2000$28.7265
1/25/2000$28.7265
1/26/2000$28.7265
1/27/2000$28.7265
1/28/2000$28.7265
1/31/2000$28.7265
2/1/2000$28.7265
2/2/2000$28.7265
2/3/2000$28.7265
2/4/2000$28.7265
2/7/2000$28.7265
2/8/2000$28.7265
2/9/2000$28.7265
2/10/2000$28.7265
2/11/2000$28.7265
2/14/2000$28.7265
2/15/2000$28.7265
2/16/2000$28.7265
2/17/2000$28.7265
2/18/2000$28.7265
2/22/2000$28.7265
2/23/2000$28.7265
2/24/2000$28.7265
2/25/2000$28.7265
2/28/2000$28.7265
2/29/2000$28.7265
3/1/2000$28.7265
3/2/2000$28.7265
3/3/2000$28.7265
3/6/2000$28.7265
3/7/2000$28.7265
3/8/2000$28.7265
3/9/2000$28.7265
3/10/2000$28.7265
3/13/2000$28.7265
3/14/2000$28.7265
3/15/2000$28.7265
3/16/2000$28.7265
3/17/2000$28.7265
3/20/2000$28.7265
3/21/2000$28.7265
3/22/2000$28.7265
3/23/2000$28.7265
3/24/2000$28.7265
3/27/2000$28.7265
3/28/2000$28.7265
3/29/2000$28.7265
3/30/2000$28.7265
3/31/2000$27.9991
4/3/2000$26.4115
4/4/2000$21.967
4/5/2000$23.4968
4/6/2000$25.9741
4/7/2000$28.7265
4/10/2000$28.7265
4/11/2000$26.8899
4/12/2000$24.3915
4/13/2000$20.198
4/14/2000$13.8379
4/17/2000$15.2987
4/18/2000$21.1647
4/19/2000$22.8484
4/20/2000$20.6471
4/24/2000$17.7373
4/25/2000$18.8596
4/26/2000$17.4659
4/27/2000$15.449
4/28/2000$15.9493
5/1/2000$17.292
5/2/2000$15.4739
5/3/2000$16.8714
5/4/2000$15.7566
5/5/2000$15.6045
5/8/2000$13.6435
5/9/2000$12.8302
5/10/2000$11.9182
5/11/2000$12.5712
5/12/2000$11.8616
5/15/2000$12.2375
5/16/2000$14.0499
5/17/2000$13.4744
5/18/2000$12.8887
5/19/2000$11.4234
5/22/2000$10.3314
5/23/2000$8.1057
5/24/2000$8.1526
5/25/2000$7.746
5/26/2000$9.8172
5/30/2000$8.6556
5/31/2000$8.017
6/1/2000$10.9126
6/2/2000$14.8324
6/5/2000$14.8138
6/6/2000$13.6927
6/7/2000$15.672
6/8/2000$16.8056
6/9/2000$18.6403
6/12/2000$24.3192
6/13/2000$22.1849
6/14/2000$24.617
6/15/2000$23.9411
6/16/2000$23.1901
6/19/2000$21.7565
6/20/2000$23.9398
6/21/2000$26.2764
6/22/2000$25.8912
6/23/2000$24.96
6/26/2000$26.416
6/27/2000$26.7832
6/28/2000$28.7265
6/29/2000$28.7265
6/30/2000$28.7265
7/3/2000$28.3418
7/5/2000$27.5259
7/6/2000$26.7968
7/7/2000$26.6034
7/10/2000$27.7982
7/11/2000$27.2823
7/12/2000$26.9009
7/13/2000$26.3458
7/14/2000$25.0313
7/17/2000$24.853
7/18/2000$24.4089
7/19/2000$23.2401
7/20/2000$23.2826
7/21/2000$22.2711
7/24/2000$18.4812
7/25/2000$17.9362
7/26/2000$17.9667
7/27/2000$15.2844
7/28/2000$12.555
7/31/2000$11.5237
8/1/2000$12.6353
8/2/2000$12.4094
8/3/2000$13.0238
8/4/2000$15.7521
8/7/2000$17.1169
8/8/2000$14.4149
8/9/2000$14.3408
8/10/2000$13.0359
8/11/2000$13.8147
8/14/2000$13.3022
8/15/2000$13.2838
8/16/2000$14.0179
8/17/2000$12.5752
8/18/2000$12.0097
8/21/2000$12.2398
8/22/2000$11.8589
8/23/2000$11.1961
8/24/2000$10.6204
8/25/2000$10.5981
8/28/2000$11.5413
8/29/2000$11.5846
8/30/2000$14.92
8/31/2000$13.5338
9/1/2000$15.7443
9/5/2000$17.656
9/6/2000$17.606
9/7/2000$16.2045
9/8/2000$16.1533
9/11/2000$14.3022
9/12/2000$13.2051
9/13/2000$13.7808
9/14/2000$14.3706
9/15/2000$12.8618
9/18/2000$11.932
9/19/2000$12.0644
9/20/2000$11.502
9/21/2000$11.0178
9/22/2000$10.5175
9/25/2000$9.4029
9/26/2000$8.8422
9/27/2000$8.5941
9/28/2000$9.9457
9/29/2000$9.7071
10/2/2000$7.0938
10/3/2000$5.4651
10/4/2000$6.2623
10/5/2000$5.552
10/6/2000$4.8749
10/9/2000$6.3252
10/10/2000$7.2682
10/11/2000$5.8949
10/12/2000$4.6822
10/13/2000$5.004
10/16/2000$4.5056
10/17/2000$3.7779
10/18/2000$3.6722
10/19/2000$2.996
10/20/2000$3.0269
10/23/2000$3.2391
10/24/2000$2.8286
10/25/2000$2.2196
10/26/2000$1.6156
10/27/2000$1.1156
10/30/2000$1.4019
10/31/2000$1.8897
11/1/2000$3.2
11/2/2000$2.538
11/3/2000$2.6167
11/6/2000$2.5514
11/7/2000$3.4829
11/8/2000$3.0087
11/9/2000$2.1527
11/10/2000$2.2452
11/13/2000$1.9054
11/14/2000$2.0401
11/15/2000$1.7371
11/16/2000$1.4426
11/17/2000$0.7402
11/20/2000$0.7508
11/21/2000$0.0096
11/22/2000$0
11/24/2000$0.7115
11/27/2000$0.1029
11/28/2000$0.4325
11/29/2000$0.075
11/30/2000$0
12/1/2000$0
12/4/2000$0.0415
12/5/2000$0
12/6/2000$0

* Data shown are adjusted forward for all stock splits between the IPO and 12/6/00.

** Purchases on a date not listed in the chart above have no artificial inflation.

*** Purchases in the IPO itself at $16.00 per share have no artificial inflation.