By Jaspreet Singh and Jeff Mason WASHINGTON, Dec 2 (Reuters) - Entrepreneur Michael Dell and his wife, Susan, will deposit $250 in the individual investment accounts of 25 million American children in a$6.25 billion philanthropic pledge as part of the ​Trump administration's Invest America initiative. The initiative, known as "Trump accounts", was created this year under President Donald Trump's One Big ‌Beautiful Bill Act and has sparked a scramble by financial firms looking to participate. The U.S. Tr ...