I was going to snark that there’s no period after the “S” because Harry Truman had no middle name. But luckily I googled it first, because it turns out that’s not correct! You use the period even though the S doesn’t stand for anything. Weird!
I saw the same thing, but then I read another thing from a different result and came here to post. However, upon returning to that second result I realize that I was skimming too quickly and misread it. Thank you for your Google.
I checked to see if Harry was a nickname for Harold–it’s not–but I didn’t know the bit about his middle initial. I guess you add an S for Savings.