Readings & Meanings:
ま（ける）to lose, to be defeated
ま（かす）to beat, to defeat
to bear, to be indebted to
They held out their hands to loan companies (salaryman loan companies, with high interest rates), and now they bear huge debts.
He's great in a match.
If I turn out to be the loser, it would be better to die.
What's your New Year's resolution?
Mister, since I'm buying the fish, could you please give me a 100 yen discount on the vegetables.
貝 (Kai-hen) is the radical. It's a pictograph of a shellfish, and it refers to goods, commodities, etc., because of the ancient shell currency used in that part of the world, long ago.
The top part depicts a crouching figure. Think of someone crouching under a great load.
Therefore, the "burden" part of this kanji's meaning is clear: to bear a heavy debt is to bear a great weight indeed.
Losing is also a burden, I suppose.
If you really want to remember this kanji, just watch Hikaru no Go. The loser of the game says either 負けました or ありません, every time he doesn't win. You will never forget the word for "to lose" if you watch the whole series (and it's quite easy to get hooked).