Company: EFR
Filing Date: 2025-03-31
Form Type: 424B3
Source: 0001076598-25-000009
Chunk: 0

Company: Eaton Vance Senior Floating-Rate Trust
Filing Date: 2025-03-31
Form: 424B3
Chunk 0
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Filed pursuant to Rule 424(b)(3)
File No. 333-266343

<div align='center'>EATON VANCE SENIOR FLOATING-RATE TRUSTSupplement to Prospectus dated March 31, 2023</div>

The following replaces the Financial Highlights contained in the Prospectus:

Selected data for a Common Share outstanding during the periods stated.

|                                                                                           |     | Year Ended October 31, |    2024 |      |     |   |    2023 |      |     |   |    2022 |      |     |   |    2021 |    |     |   |    2020 |    |
|:------------------------------------------------------------------------------------------|:----|:-----------------------|--------:|-----:|:----|:--|--------:|:-----|:----|:--|--------:|:-----|:----|:--|--------:|---:|:----|:--|--------:|:---|
| Net asset value - Beginning of year (Common shares)                                       |     | $                      |   12.77 |      |     | $ |   12.28 |      |     | $ |   14.30 |      |     | $ |   13.50 |    |     | $ |   14.51 |    |
| Income (Loss) From Operations                                                             |     |                        |         |      |     |   |         |      |     |   |         |      |     |   |         |    |     |   |         |    |
| Net investment income(1)                                                                  |     | $                      |    1.50 |      |     | $ |    1.45 |      |     | $ |    0.92 |      |     | $ |    0.72 |    |     | $ |    0.81 |    |
| Net realized and unrealized gain (loss)                                                   |     |                        |    0.27 |      |     |   |    0.44 |      |     |   |   (1.93 | )    |     |   |    0.91 |    |     |   |   (0.87 | )  |
| Distributions to preferred shareholders                                                   
 From net investment income(1)                                                             |     |                        |   (0.22 |    ) |     |   |   (0