NEW YORK (TheStreet) -- Shares of Aspen Technology (AZPN)  closed down by 5.71% to $34.21 on heavy trading volume on Wednesday, as Benchmark downgraded the stock to "hold" from "buy" this morning. The firm has a $34 price target.

The Burlington, MA-based company is a provider of process optimization software solutions.

The downgrade comes after yesterday's announcement that the company intends to acquire London-based KBC Advanced Technologies for about 158 million euros (about $230 million). KBC Advanced Technologies is engaged in the provision of software technology and consultancy to the hydrocarbon industry.

"On the one hand, the deal brings significant positives to the story in the form of KBC's leading refinery models, oil & gas customer relationships, and the deal is expected to be accretive to cash flow and non-GAAP EPS by the end of FY17," Benchmark said in an analyst note.

However, the firm suspects that investors will take the acquisition as a cause to start worrying about further unanticipated integration challenges emerging over the next couple of quarters, which is likely to limit upside potential, especially with record low oil prices.

About 1.15 million of the company's shares were traded by this afternoon, well above its average of 544,088 shares per day.

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