To clarify, I'm interested in securities, competition and anti-trust and megers and aquisitions.
Jeez...! A high schooler knows about all this stuff? Wow.
I happen to work in the securities industry. That said, I think you need to worry about getting through college before you worry about law school. That said, major in something that interests you, and it sounds like economics and finance interest you.
And take a look at the LSAT if you already haven't. One major skill you are going to need on there (and in law school too) is the ability to read fast, understand, and analyze what you are reading. This suggests majors like English and History would be beneficial, and it is apparent that a lot of people with those majors get accepted to law school.
At the very least, read a lot and analyze what you read. Reading comprehension is one skill that is best developed over a long period of time, it's something that's hard to cram for.