$BBY calls double overnight

Option traders posted big gains in Best Buy (BBY) today on positions opened only one session earlier.

Just yesterday, Market Rebellion’s Unusual Activity Service found that 4,900 Weekly $80 calls expiring this Friday were bought for $0.60 to $1.53 with shares at $80.89. Open interest in the strike was 1,364 contracts before the activity appeared, indicating that this was fresh buying.

Those calls have traded for as much as $2.60 so far today, about 2.5 times their average purchase price. The stock rose 1.8% at the same time, showing how quickly options can far outpace gains in their underlying shares.

Long calls lock in the price where a stock can be purchased, gaining with a rally and providing leverage to the underlying shares. The contracts can quickly lose value if the stock stalls or pulls back but also carry less risk than owning the shares themselves.

BBY spiked to $82.48 in early trading but has pulled back to $81.08, off 0.6% so far this morning. The electronics retailer topped earnings and sales expectations yesterday morning.