It looks to me like one share. The certificate it was printed on says in the corner that it can’t be for more than 100 shares which presumably is to avoid fraud by someone trying to change the amount
My guess too but then I can’t think, knowing my brother, that he’d bother to buy one share. Seems odd. But, he was a bit odd too so…maybe? Hard to guess.
Also seems a lot of work and effort to send such a certificate for one share but I dunno…it was a different time back then. The weird way it is done suggests to me that either it was 100 (i.e. you bought the max for that certificate) or 1. I have NO idea.
It can’t be one hundred, because the engraved template says “LESS than 100 shares” (their emphasis). “*1*”, “*ONE*” and “0 TENS” / “1 UNITS” (punched on the right) all clearly indicate one single share.
Good point. I was (optimistically) thinking “ONE” might be the max of that piece of paper.
Seems crazy to issue that whole thing for one share and seems crazy my brother would do that but…there it is.
If you bought one share, they’d have to issue that to you. No way around it.
He may have been awarded it or won it somehow. Sometimes people would buy a single share of a company because that entitled them to get a copy of a prospectus and to attend the annual meeting and ask questions and be a gadfly.
I think it is because back in that time you had to buy stock in blocks of 100. By denoting a certificate was lessthan 100, it was clear that was not a block.
That makes sense. You might buy $1000 worth of stock which would be a few blocks plus a remainder.
Looking at the right hand margin suggests that it’s a one share cert as well.
The purchaser might have bought this token share to receive a shareholder perk. Or the purchaser may have owned, say, 100 shares and have signed up with a DRIP program (dividend reinvestment plan), whereby dividends are paid out in shares rather than in cash. Back during the 1960s, brokers charged stiff commissions for stock purchases and sales: shares received via DRIPs were commission free. The purchaser may have sold the bulk of their stock, but retained the one share certificate as a keepsake. Or the cert could have been misplaced. Anyway we’re discussing a possible $600 upside minus taxes.
True. Per share. The OP mentions they have several certificates. Perhaps others are for more than one share.
Note that the ticker symbol was “IPC” (not “IPL”), and it may have been recycled after the merger/buyout, so unless the stock split info specifically refers to Interstate, it could be some other company. Alliant has had one 2-for-1 split.
FTR, splithistory.com has no record of IPC splits. So we’re down to ~~1.1*90 = $100 per original share. Of course the stock may not have made its way into their records.
I am, strangely, way too invested in this thread. 
So you’re not going to split?