This week brings to close yet another year of gains for the stock market, the 6^th straight in this amazing bull.

The benchmark S&P 500 started off 2014 at 1848 and as of Friday the index sits at 2088. Not as good as 2013, but still a good year.

Some of the top industries of the year include airlines, semiconductors, hospitals, aluminum, internet service providers and residential REITs.

Another industry cracking this year’s top 10 probably comes at no surprise: biotechnology.

With so many biotech names making the headlines this year, investors may find it hard to know which company’s stocks performed the best.

Below is a list of the top 5 performing biotech stocks of 2014.

Coming in as the number 5 biotech performer would be Achillion Pharmaceuticals (NASDAQ: ACHN).

After starting the year at under $4/share, Achillion increased by 278 percent over the next 12 months and closed at $12.82 on Friday.

In 4^th place would be Bluebird Bio (NASDAQ: BLUE) with a 320 percent increase during the same 12-month period of time.

Bluebird ended last week at $89.99 after starting the year off at just under $21/share.

Next up on the list would be TG Therapeutics (NASDAQ: TGTX).

TG has increased by 321 percent during 2014, going from around $4/share to start the year and closing at $16.18 on Friday.

The 2^nd biggest biotech gainer of 2014 comes from Receptos (NASDAQ: RCPT).

Receptos increased by 357 percent this year. Seeing the stock above $100 for the last 2 months makes it hard to remember that Receptos wasn’t even a $30 stock at the beginning of 2014.

And the number 1 performance of 2014 by a biotech stock comes from Agios Pharmaceuticals (NASDAQ: AGIO).

Agios has almost quadrupled over the last year having gained 371 percent. The stock closed on Friday at $114.43.

Obviously, investors must conduct their own due diligence before investing in any stock, but stocks having the best gains now could very well be the stocks with the most momentum going into 2015.

The biotech stocks considered for this review were confined to those over $5 per share that traded at least 500K shares a day based on a 90-day average.