Generally speaking, fund managers should err towards not accepting capital commitment increases after the Fund's Fundraising Period has ended. Issues of fiduciary duty can be implicated, depending on the circumstances, and enough of a total increase can even trigger amended regulatory filings (which are public).

In a practical sense, any such acceptances should be one-off exceptions made within a reasonable amount of time from the Fundraising Period ending. Within 3 months might be nominal, within 6 months might start to raise eyebrows, and beyond that said issues of fiduciary duty may become more pronounced.

Note that the above guidelines are general, and the viability of any such acceptances may also depend on a Fund's particular circumstances (markups, exits, etc.). We strongly recommend discussing these  your fund administration team first.