Form 485BXT VANGUARD INSTITUTIONAL

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Post-Effective Amendment No. 94 was filed under Rule 485(b)(1)(iii) on September 19, 2024, for the sole purpose of delaying, until October 18, 2024, the pending effective date of the Trust’s 93^rd Post-Effective Amendment. 

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Post-Effective Amendment No. 93 was filed under Rule 485(b)(1)(iii) on August 22, 2024, for the sole purpose of delaying, until September 20, 2024, the pending effective date of the Trust’s 92^nd Post-Effective Amendment. 

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Post-Effective Amendment No. 92 was filed under Rule 485(b)(1)(iii) on July 25, 2024, for the sole purpose of delaying, until August 23, 2024, the pending effective date of the Trust’s 91^st Post-Effective Amendment. 

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Post-Effective Amendment No. 91 was filed under Rule 485(b)(1)(iii) on June 27, 2024, for the sole purpose of delaying, until July 26, 2024, the pending effective date of the Trust’s 90^th Post-Effective Amendment. 

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Post-Effective Amendment No. 90 was filed under Rule 485(b)(1)(iii) on May 30, 2024, for the sole purpose of delaying, until June 28, 2024, the pending effective date of the Trust’s 89^th Post-Effective Amendment. 

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Post-Effective Amendment No. 89 was filed under Rule 485(b)(1)(iii) on May 2, 2024, for the sole purpose of delaying, until May 31, 2024, the pending effective date of the Trust’s 87^th Post-Effective Amendment. 

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Post-Effective Amendment No. 87 was filed under Rule 485(b)(1)(iii) on April 4, 2024, for the sole purpose of delaying, until May 3, 2024, the pending effective date of the Trust’s 86^th Post-Effective Amendment. 

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Post-Effective Amendment No. 86 was filed under Rule 485(b)(1)(iii) on March 7, 2024, for the sole purpose of delaying, until April 5, 2024, the pending effective date of the Trust’s 85^th Post-Effective Amendment. 

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Post-Effective Amendment No. 85 was filed under Rule 485(b)(1)(iii) on February 8, 2024, for the sole purpose of delaying, until March 8, 2024, the pending effective date of the Trust’s 84^th Post-Effective Amendment. 

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Post-Effective Amendment No. 84 was filed under Rule 485(b)(1)(iii) on January 11, 2024, for the sole purpose of delaying, until February 9, 2024, the pending effective date of the Trust’s 83^rd Post-Effective Amendment. 

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Post-Effective Amendment No. 83 was filed under Rule 485(b)(1)(iii) on December 14, 2023, for the sole purpose of delaying, until January 12, 2024, the pending effective date of the Trust’s 82^nd Post-Effective Amendment. 

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Post-Effective Amendment No. 82 was filed under Rule 485(b)(1)(iii) on November 16, 2023, for the sole purpose of delaying, until December 15, 2023, the pending effective date of the Trust’s 81^st Post-Effective Amendment. 

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Post-Effective Amendment No. 81 was filed under Rule 485(b)(1)(iii) on October 19, 2023, for the sole purpose of delaying, until November 17, 2023, the pending effective date of the Trust’s 80^th Post-Effective Amendment.  

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Post-Effective Amendment No. 80 was filed under Rule 485(a)(2) on July 21, 2023, to register shares of Vanguard Extended Market Index Fund, a new series of the Trust (the “Acquiring Fund”), in connection with a reorganization of a predecessor fund (Vanguard Extended Market Index Fund, a series of Vanguard Index Funds) with and into the Acquiring Fund. The Acquiring Fund is identical in management to the predecessor fund, and the investment objective, strategies, and policies remain unchanged. Post-Effective Amendment No. 80 originally requested that the Amendment become effective on October 20, 2023.