Pharmaceutical sector-specific exchange traded funds showed mixed results Tuesday after AbbVie (NYSE: ABBV) agreed to acquire Allergan (NYSE: AGN) for $63 billion.

Among the largest pharma-specific ETFs, Invesco Dynamic Pharmaceuticals Portfolio (NYSEArca: PJP) was up 0.1%, SPDR Pharmaceuticals ETF (NYSEArca: XPH) gained 2.4%, iShares U.S. Pharmaceuticals ETF (NYSEArca: IHE) rose 1.9% and VanEck Vectors Pharmaceutical ETF (NYSEArca: PPH) was 0.1% higher on Tuesday,

AbbVie agreed to buy out Allergan for about $63 billion as the two drugmakers bet that combined they will deliver new sources of growth they have struggled to find on their own, the Wall Street Journal reports.

AbbVie’s acquisition of Allergan would cement a dominant position in the $8 billion-plus market for Botox and other beauty drugs, along with a number of popular eye treatments. The combined line could help AbbVie shore up weakness as it sees the end of patent protection for the world’s top-selling drug, Humira.

Additionally, companies’ portfolios have some overlap in treatments for brain, women’s-health, stomach and other disorders. However, their combined businesses would help AbbVie move into into beauty lines from frown-line smoothing, eyelash lengthening and double-chin removal.

Triggering the disparate performances among the various pharmaceutical ETFs on Tuesday, AbbVie shares plunged 16.3% while Allergan shares surged 25.4% in response to the deal.

The varying performances in the pharmaceutical ETF segment goes to show the importance of looking closer into an ETF holdings and considering one’s own goals before making the final decision to invest.

Specifically, something like XPH, which includes a 4.9% tilt toward AGN, follows a more equally weighted indexing methodology, so smaller or mid-sized companies hold a larger weight in the portfolio. These types of companies are also some of biggest take-over targets when larger players are looking to shop around for an acquisition.

On the other hand, ETFs that follow more cap-weighted indexing methodologies, such as PPH, will tilt toward some of the largest companies in the space, including a 5.0% position in ABBV.

For more information on the pharma sector, visit our pharmaceuticals category.