Hmmm...
That, if you're unaware of what you're looking at, is the option chain for the "XLF", the financial sector "spyder" ETF, for April expiry.
The April $16 and $17 PUTs have enormous open interest. The $16s have been there for quite a while.
The $17s, however, have not.
At first blush you'd look at this and think it was a spread, which is not all that unusual. But then you look more-closely and on 1/24 you find that 50,000 $17 PUTs were opened against 44,000 open interest (approximately) and that was all the material movement through the end of the month.
Then, on the first of February, an obvious spread appears to have traded for 25,000 contracts.
And then the big daddy appeared -- a monster set of trades on the 5th -- and both "stuck" the next day.
That is, these were not daytrades. They're positional. And they're still there.
Assuming this was a "spread", the person executing it spent about 20 cents. Since each option is 100 shares this is $20.00 times 100,000 (approximately), or $2 million.
On a 10% decline they will net 5x their bet, or $10 million.
If the decline is larger they get nothing more, as the short PUT sold against the long (assuming it's a spread) caps their profit. But that's a hell of a lot of money to slap on the table -- unless you know something.
We'll see if the person who placed the trade indeed does.