0000844779 2025-05-01 2026-04-30 0000844779 bf:C000237396Member 2025-05-01 2026-04-30 0000844779 bf:C000237396Member 2026-04-30 0000844779 bf:OtherAssetsLessLiabilitiesMember bf:C000237396Member 2026-04-30 0000844779 us-gaap:RepurchaseAgreementsMember bf:C000237396Member 2026-04-30 0000844779 bf:USTreasuryObligationsMember bf:C000237396Member 2026-04-30 iso4217:USD pure bf:Holding 0000844779 false N-1A N-CSR BlackRock Funds 2026-04-30 Circle Reserve Fund Institutional Shares USDXX This annual shareholder report contains important information about Circle Reserve Fund (the “Fund”) for the period of May 1, 2025 to April 30, 2026. annual shareholder report You can find additional information about the Fund at <span style="color: rgb(0, 0, 0); font-weight: bold; text-decoration-line: none; font-family: 'arial'; font-size: 8pt; line-height: 10.4pt; text-align: justify;">blackrock.com/fundreports</span>. You can also request this information by contacting us at (800) 441‑7450. blackrock.com/fundreports (800) 441‑7450 <div style="font-kerning: none; font-family: 'arial'; font-size: 10pt; font-weight: bold; color: rgb(0, 0, 0); margin: 0px 0px -0.18pt 0px;">What were the Fund costs for the last year?</div> <div style="font-weight: 400; font-kerning: none; font-family: 'arial'; font-size: 9pt; color: rgb(0, 0, 0); margin: 0px;">(based on a hypothetical $10,000 investment)</div> <table style="page-break-inside: avoid; margin-top: 2pt; break-inside: avoid; table-layout: auto; width: 100%; border-collapse: collapse;"> <tr style="break-after: avoid; break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; font-size: 9pt; line-height: 11pt; color: rgb(0, 0, 0); font-weight: bold; background-color: rgb(255, 206, 0); vertical-align: bottom; text-align: left; padding: 2pt 0 2pt 0;">Class name</td> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; font-size: 9pt; line-height: 11pt; color: rgb(0, 0, 0); font-weight: bold; background-color: rgb(255, 206, 0); text-align: center; vertical-align: bottom; padding: 2pt 0 2pt 0;">Costs of a $10,000<br/>investment</td> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; font-size: 9pt; line-height: 11pt; color: rgb(0, 0, 0); font-weight: bold; background-color: rgb(255, 206, 0); text-align: center; vertical-align: bottom; padding: 2pt 0 2pt 0;">Costs paid as a percentage of a <br/>$10,000 investment</td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); overflow-x: hidden; vertical-align: bottom; font-size: 8pt; line-height: 10pt; text-align: left; padding: 4pt 0 2pt 0;">Institutional Shares</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); vertical-align: bottom; text-align: center; font-size: 8pt; line-height: 10pt; padding: 4pt 0 2pt 0;"><span style="float: none;">$</span>9</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); vertical-align: bottom; text-align: center; font-size: 8pt; line-height: 10pt; white-space: nowrap; padding: 4pt 0 2pt 0;">0.09<span>%</span></td> </tr> </table> 9 0.0009 <div style="font-family: 'arial'; font-weight: bold; font-size: 10pt; text-align: left; letter-spacing: normal; text-transform: none; font-kerning: none; color: rgb(0, 0, 0); background-color: rgb(255, 206, 0); border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt; padding: 2pt 0px 1.5pt 0px; margin: 0px;">Key Fund statistics</div> <table style="break-inside: avoid-page; page-break-inside: avoid; table-layout: auto; width: 100%; border-collapse: collapse; margin-top: 0px;"> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 6pt 0 6pt;">Net Assets</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); white-space: nowrap; font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 0 6pt;"><span style="float: none;">$</span>66,367,042,789</td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 6pt 0 6pt;">Number of Portfolio Holdings</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); white-space: nowrap; font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 0 6pt;">29</td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 6pt 0 6pt;">Net Investment Advisory Fees</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); white-space: nowrap; font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 0 6pt;"><span style="float: none;">$</span>30,854,444</td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: 0; padding: 1.6pt 6pt 0 0;"><strong>Current seven-day yields as of </strong><strong>April 30, 2026</strong><strong> (The 7-day SEC Yield may differ from the 7-Day Yield shown due to the fact that the 7-Day SEC Yield excludes distributed capital gains.)</strong></td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 0 6pt;"></td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 6pt 0 6pt;">7-Day SEC Yield</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); white-space: nowrap; font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 0 6pt;">3.60<span>%</span></td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; overflow-x: hidden; font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 8pt; line-height: 10pt; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 6pt 1.6pt 6pt;">7-Day Yield</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; color: rgb(0, 0, 0); white-space: nowrap; font-size: 8pt; line-height: 10pt; width: 12%; vertical-align: bottom; padding: 1.6pt 6pt 1.6pt 6pt;">3.60<span>%</span></td> </tr> </table> 66367042789 29 30854444 <div style="font-kerning: none; font-family: 'arial'; font-size: 10pt; font-weight: bold; color: rgb(0, 0, 0); margin: 0px 0px -0.18pt 0px;">What did the Fund invest in?</div> <div style="font-weight: 400; font-kerning: none; font-family: 'arial'; text-align: justify; color: rgb(0, 0, 0); font-size: 9pt; line-height: 11.4pt; margin: 0px;">(as of April 30, 2026)</div> <div style="font-family: 'arial'; font-weight: bold; font-size: 10pt; text-align: left; letter-spacing: normal; text-transform: none; font-kerning: none; color: rgb(0, 0, 0); background-color: rgb(255, 206, 0); border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt; padding: 2pt 0px 1.5pt 0px; margin: 0px;"><b>Portfolio composition</b></div> <table style="page-break-inside: avoid; break-inside: avoid; table-layout: auto; width: 100%; border-collapse: collapse; margin-top: 0px;"> <tr style="break-after: avoid; break-inside: avoid-page; page-break-inside: avoid; height: auto; font-family: 'arial'; font-style: italic; font-size: 8pt; line-height: 10pt; border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; line-height: 11pt; color: rgb(0, 0, 0); font-size: 8pt; white-space: nowrap; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 0 0 6pt;"><em>Asset Type</em></td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; font-kerning: none; font-family: 'Arial'; line-height: 11pt; color: rgb(0, 0, 0); font-size: 8pt; white-space: nowrap; vertical-align: bottom; padding: 1.6pt 0 0 0;"><em>Percent of<br/>Net Assets</em></td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; font-family: 'Arial'; line-height: 11pt; color: rgb(0, 0, 0); width: auto; text-align: left; font-size: 8pt; white-space: nowrap; vertical-align: bottom; padding: 1.6pt 0 0 0;"></td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; font-family: 'arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; color: rgb(0, 0, 0); overflow-x: hidden; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 0 0 6pt;">Repurchase Agreements</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 2pt 0 0 0;">70.8</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); text-align: left; white-space: nowrap; width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 1.6pt 0 0 0;"><span>%</span></td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; font-family: 'arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; color: rgb(0, 0, 0); overflow-x: hidden; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 0 0 6pt;">U.S. Treasury Obligations</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 2pt 0 0 0;">28.8</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); text-align: left; white-space: nowrap; width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 1.6pt 0 0 0;"><span style="visibility: hidden; margin-left: -7pt;">%</span></td> </tr> <tr style="break-inside: avoid-page; page-break-inside: avoid; height: auto; font-family: 'arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: rgb(0, 0, 0); border-bottom-style: solid; border-bottom-width: 0.5pt;"> <td style="break-inside: avoid-page; page-break-inside: avoid; font-kerning: none; color: rgb(0, 0, 0); overflow-x: hidden; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; font-weight: normal; text-align: left; width: 100%; vertical-align: bottom; text-indent: -6pt; padding: 1.6pt 0 1.6pt 6pt;">Other Assets Less Liabilities</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; text-align: right; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 2pt 0 1.6pt 0;">0.4</td> <td style="font-weight: 400; break-inside: avoid-page; page-break-inside: avoid; vertical-align: bottom; font-kerning: none; color: rgb(0, 0, 0); text-align: left; white-space: nowrap; width: auto; font-family: 'Arial'; font-style: normal; font-size: 8pt; line-height: 10pt; border-bottom-color: initial; border-bottom-style: none; border-bottom-width: initial; padding: 1.6pt 0 1.6pt 0;"><span style="visibility: hidden; margin-left: -7pt;">%</span></td> </tr> </table> 0.708 0.288 0.004 Past performance is not an indication of future results. Visit <span style="color: rgb(0, 0, 0); font-weight: bold; text-decoration-line: none; font-family: 'arial'; font-size: 8pt; line-height: 10.4pt; text-align: justify;">blackrock.com</span> for more recent yield information.