Not all portfolios are perfect, and if you're in your 40s and 50s, you probably have a variety of old accounts or have inherited accounts that need some polishing up. Merging gifted assets and inherited assets that were meant to meet someone else's goals into your portfolio can be a tax challenge unless you know where to find important information. Making sure you have all of your accounts well organized will save you money, as well.

Gifted Assets

You don't owe tax when assets are given to you — though, depending on the size of the gift, the giver might — but you do receive the giver's basis in the asset. Remember, the basis is the amount originally paid for the asset, plus any additional deposits, including reinvested dividends, interest, and capital gains. Don't forget to ask the giver for his basis when you receive the gift. You'll need to know your capital gain amount when you sell.

Once you know that basis, you can treat the gifted asset like any other of your investments. Do an investment review, and if it doesn't fit your asset allocation or if it's underperforming comparable investments or the most appropriate index, it's time to sell.

Inherited Assets

You have some tax planning to do if you inherit a retirement account such as an IRA or a 401(k), but other than those special accounts, you don't owe tax when you inherit money. In some cases, the estate of the person you're inheriting from might owe tax; hopefully, she has paid the tax before distributing your inheritance to you. The advantage of inheritances over gifts is that you get what's called a stepped-up basis on the asset — instead of inheriting the giver's basis as you would with a gift, your new basis is the value of the asset on the day the giver died. Some large estates are valued as of six months after the day the individual dies — ask the executor of the estate whether this is the case in your situation.

If you've inherited a retirement account, it's important to get tax advice. If the individual who owned the account was over age 70½ and was taking withdrawals, you will need to continue making withdrawals of a certain minimum amount. If the account owner was younger, you may be able to delay taking withdrawals or you may be able to take small withdrawals over your lifetime. If you inherit your spouse's retirement account, you can roll the proceeds over into your own account and in many cases delay taking withdrawals. The reason for trying to delay withdrawals is to save taxes and continue the tax-deferred growth in the retirement account. This doesn't mean that you can't take money from the account if you need it; you'll just owe taxes on the amount if you do.

Your Own Accounts

It's never too late to fix a neglected investment or portfolio. Start by gathering your account statements and listing the account name, total balance, investment values, investment basis, and the amount you're contributing regularly to the account. Most brokers and investment companies keep track of the basis in the investments you bought through them for as long as you still hold the account with them. If you're not sure of a basis, call the broker and see if they have that information before deciding to move the account. If they don't know your basis, they should still be able to mail you copies of past statements. From these statements you should be able to add up all your deposits — remember to include reinvested dividends and interest as well as cash deposits.

If you're missing accounts or can't find statements, look at back tax returns for records of interest, dividends, or taxable capital gains. The tax return schedules that report these incomes will list the investment name. Call the investment company and check for accounts using your social security number.