Brett and Gil nail it right on the head in that this is not advisable unless you expense these items in the period between the term sheet was signed and the money was in the bank.
As previous writers stated, always think of your fiduciary responsibility to backers and shareholders. Will paying or reimbursing founders for past expenses breach this duty? I would also concur that ultimately the duty to fully disclose expenses and only deal with those expenses after full consent from interested parties has been obtained is key. The last thing you want is an impression that you have lost faith in the viability of the venture want to cover your own costs at the expense of the business at an early stage. If it’s a minimal amount of expenses it will likely not be an issue but always be mindful of legal obligations to follow internal procedures and the terms of funding and lastly the impression this can convey to potential investors
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