Cabaletta Bio, Inc.
US ˙ NasdaqGS ˙ US12674W1099

SecurityCABA / Cabaletta Bio, Inc.
InstitutionSuperstring Capital Management Lp
Latest Disclosed Ownership1,066,239 shares
Latest Disclosed Value $ 2,868,183
Superstring Capital Management Lp reports 52.69% decrease in ownership of CABA / Cabaletta Bio, Inc.

On May 14, 2026 - Superstring Capital Management Lp filed a 13F-HR form disclosing ownership of 1,066,239 shares of Cabaletta Bio, Inc. (US:CABA) valued at $2,868,183 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,253,550 shares of Cabaletta Bio, Inc.. This represents a change in shares of -52.69% during the quarter. The current value of the position is $3,817,136 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-14 2026-03-31 13F CABALETTA BIO COM 12674W109 1,066,239 -1,187,311 -52.69 2,868 -41.88 2.0491
2026-02-17 2025-12-31 13F CABALETTA BIO COM 12674W109 2,253,550 709,025 45.91 4,935 36.55 2.6423
2025-11-14 2025-09-30 13F CABALETTA BIO COM 12674W109 1,544,525 483,761 45.60 3,614 124.19 3.5607
2025-08-14 2025-06-30 13F CABALETTA BIO COM 12674W109 1,060,764 601,792 131.12 1,612 153.86 1.9091
2025-05-15 2025-03-31 13F CABALETTA BIO COM 12674W109 458,972 -363,321 -44.18 636 -65.97 0.7563
2025-02-14 2024-12-31 13F CABALETTA BIO COM 12674W109 822,293 690,498 523.92 1,867 200.00 1.6163
2024-11-14 2024-09-30 13F CABALETTA BIO COM 12674W109 131,795 -8,100 -5.79 622 -40.54 0.5445
2024-08-14 2024-06-30 13F CABALETTA BIO COM 12674W109 139,895 -150,902 -51.89 1,046 -78.91 1.3191
2024-05-15 2024-03-31 13F CABALETTA BIO COM 12674W109 290,797 290,797 4,961 3.2803
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.