Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of light-based technology specialist Cymer (NASDAQ: CYMI) soared a whopping 49% today after Dutch chip-equipment giant ASML (ASML 1.14%) offered to acquire it for about $2.55 billion.

So what: Cymer shareholders will receive $20 in cash for each share owned plus 1.15 ASML shares, representing about a 60% premium to Cymer's closing value on Monday. ASML is making the move to speed up the development of extreme ultraviolet semiconductor lithography (needed to produce next-generation mobile chips), but judging from its own stock's 9% drop today, Mr. Market thinks it's a rather expensive way to do it.

Now what: The transaction is expected to close in the first half of 2013 and be accretive to ASML's EPS two years after that. "We believe that this transaction will improve our capabilities to bring new technologies to our customers, and will deliver value to Cymer's and ASML's shareholders," said ASML President and CEO Eric Meurice. Given the seemingly lofty price that ASML is paying, however, I wouldn't be too quick to buy into that optimism.