Negotiating job offers is a skill, and many are reluctant to even attempt it. Like interviewing, negotiation is something that most professionals may only do a few times (or less) a decade, so it's not the type of skill that gets honed through regular use.
One question that I often hear relates to scenarios where a candidate provides a target salary or range on an application or in the interview process, the employer makes an offer at or above that range, and the candidate doesn't know what to do. Conventional wisdom (and perhaps ethics) would suggest that one should accept such an offer, but when an employer matches the candidate's request it can make candidates feel their request was too low.
If you list your house for sale on a Friday and receive five full-price offers before the weekend is over, most people will tell you that you set your bar too low in a competitive market.
It could be that the salary request was "at market", but one natural reaction to having a salary request met without reluctance is that the candidate "left money on the table". This feeling is often accompanied with some regrets, and some candidates wonder whether or not they can still negotiate even though they got what they wanted.
What to Do?
It is potentially a risky endeavor, but if you choose to negotiate an offer that met your request you're going to need a reason. A big mistake that job seekers inexperienced in negotiating make is the appearance that they are negotiating just for the sake of negotiating, and employers that met your initial request will feel any new requests are not a good faith negotiation.
Did you uncover new information since setting your target number?
The primary way to negotiate a matched request is to tie a counteroffer to new information learned after you provided the original number. This typically needs to be a detail that one couldn't have reasonably expected to know at the time the desired salary was provided.
Some good examples of this include:
Responsibility - Does the job have more responsibility than you initially would have assumed?
Work/life balance - Are the expectations for hours in the office above what one would expect? Does the position require you to be "on call"?
Benefits and perks - These are usually discussed later in the interview process or even after an offer is made, so it's reasonable to assume that many job seekers will be asked for desired salary numbers well before they learn the value of the other pieces of the overall compensation package. The major variables impacting overall package value tend to be health insurance contribution, paid time-off, bonus, and stock.
Your own market value - Admitting that you underestimated your own market value it the least attractive option. A job seeker claiming this will be viewed as someone who was unprepared.
I would expect most instances where candidates submit counteroffers above their initial asking price are related to competing offers from other employers. In highly competitive markets, above average candidates may expect multiple offers with some from companies that pay employees above market rate. Using other offers as a negotiation tool has become rather common in the industry, though some employers may not be willing to engage in renegotation if an initial request was matched.
It's important to keep data on any salary numbers (historical and requested) provided during the hiring process and to be prepared with numbers handy in case you are asked. Keep in mind that companies traditionally want information on salary expectations before committing to interviews, and the process of negotiating an offer above the listed expectation can be complex (but not impossible).