| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Font Juan | SVP, Pres. & CEO, CoreSite | 222 BERKELEY STREET, BOSTON | /s/ Marina A. Breed, as attorney-in-fact | 06 Jan 2026 | 0001733553 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | AMT | Common Stock | Tax liability | $73,241 | -419 | -1.8% | $174.80 | 23,054 | 03 Jan 2026 | Direct | F1, F2 |
| Id | Content |
|---|---|
| F1 | Shares delivered to the issuer for the payment of withholding taxes in connection with the vesting of restricted stock units previously granted under the 2007 Equity Incentive Plan, as amended. |
| F2 | Includes 48 shares acquired under the issuer's employee stock purchase plan in November 2025. |